For nearly three decades, 50-year-old Hewson has been the other, some will say better, half of U2's swaggering frontman, staying at home with the kids, pets, home repairs and school run while Bono (51) struts his stuff on stages around the world for months at a time.
With a €572m personal fortune at her disposal, Hewson could live a designer-label-wearing, luxury-spa-going life of indulgence that would make the housewives of Wisteria Lane weep with envy. And yet we never see her shopping like a WAG, or appearing on reality TV.
Just what do we know about the lady behind the man once voted one of the world's most powerful?
Everyone has an opinion on Bono. Over the years, the singer has garnered a wealth of eclectic labels, from hero to hypocrite and pain in the ass.
But ask anyone who has met, interviewed or socialised with his wife and it's hard to find one with a bad word to say about her -- or indeed any words at all.
"She's very non-showbiz, very down to earth and genuine," says one reporter. "She's sharp, realistic and very normal. With someone of her status you would think there would need to be a certain level of schmoozing, but there's no bulls*** about her.
"If anything, she'd be turned off by empty flattery."
The sentiment has been echoed by her business partner Bryan Meehan, who was introduced to her when she was first setting up her make-up range, Nude.
He said: "The first thing I felt about Ali was how down to earth she was -- everyone says that after meeting her. You think about someone who is a rockstar's wife and the life she must lead, but she's the opposite to that person."
But then Hewson never signed up to be a rockstar's wife. She met her future husband when he was plain old Paul Hewson at Mount Temple Comprehensive School. She was dark-eyed Alison Stewart, a quiet girl from Raheny, daughter to housewife Joy and dad Terry, who was in the electrical trade.
Keen-eyed Bono spotted her on her first day and made up an excuse to talk to her, for which she branded him "an eeijit". Loquacious, even at a young age, Bono talked her round and became Hewson's 'first real boyfriend' when she was just 15 and he 16.
Their relationship developed after the death of Bono's mum, Iris, from an aneurysm in 1973. Caring and practical, Hewson stepped in, making sure he got to school, washed his clothes and ate well by bringing him to her own home for dinner or cooking his meals herself.
The band was taking off and newly wed Hewson decided to shelve her dreams of becoming a nurse to support her new husband and his rock 'n' roll dreams.
Instead, she concentrated on sitting her finals at DCU to get her degree in politics and sociology -- which she achieved while severely sleep deprived having given birth for the first time just two weeks previously.
As Bono's profile grew, the frontman developed unashamedly expensive tastes. Dinners out at the best restaurants around the globe routinely run into thousands of euro, and the bon viveur maintains he can only drink pricey vintage wines because he's allergic to the lower-end booze that wrecks his voice.
He covers extensive air miles in his group's Airbus A320 jet, Vertigo 3, reportedly part-owns a Â¤15m yacht, and zips around Dublin in his Italian Maserati Quattroporte, worth a cool Â¤83,133. "The job of art is to chase away ugliness," he says.
Not so, Mrs Hewson. For years, she was happy to rattle off on the school run in a 1991 Volkswagen Golf, only recently upgrading to a Mercedes estate. Even then she made sure to ask for the 'basic model', explaining to the salesman she'd no interest in anything flashy.
As a youngster, she was something of a tomboy with little interest in fashion, content to wear clothes -- and even a wedding dress -- handmade by her mum. She says: "I've never been interested in things that sparkle and shine, I'm more interested in people."
But that's not to say she hasn't enjoyed some of the trappings that come with being South Co Dublin's most wealthy housewife.
First off, she's a wife with some fabulous houses. Her main base is a Victorian mansion on Vico Road, Dalkey, with sweeping views over Scotsman's Bay.
Palatial to begin with, Hewson has overseen extensive renovations to the Temple Hill home, most recently an additional floor to accommodate a sprawling bedroom, wraparound terrace and new roof.
She wanted to make the house more eco-friendly and in recent years developed an underground plant room with a new energy-efficient boiler.
In 2004 they added to the 6,000sq ft home by buying miniature castle, Lios Beag, next door and linking the properties by corridor. Prior to that, a swimming pool had also been added.
The family often escapes to exclusive island paradises such as St Barts, but when there's no cruiser to charter or five-star hotel to check into, there's always their Â¤5m beachfront villa on Millionaire's Row, Eze-sur-Mer in France -- where the couple are currently staying, celebrating their 29th wedding anniversary -- with its six bedrooms, sprawling open-plan ground floor and celebrity neighbours including bandmate The Edge.
Increasingly, with half the family based across the pond -- eldest daughter, Jordan is studying at Columbia and, until recently, Memphis Eve was at NYU -- Hewson's base has shifted to the New York pad, a sumptuous duplex penthouse on the 27th floor of the exclusive San Remo building on the Upper West Side.
It was purchased in 2005 off another friend, Apple boss Steve Jobs, for a modest $14.9m (Â¤10.3m) and boasts the unusual claim to fame of being so exclusive that not even Madonna was allowed to live there.
Despite its terrace looking on to Central Park, the apartment, with its bronze doors and floor-to-ceiling windows, is said to be cold rather than welcoming, but it boasts amenities appealing to Hewson, who enjoys shopping at nearby Saks and Barneys, walking in Central Park, brunching at bustling French bistro Balthazar and dining at Michael White's Osteria Morini.
In Dublin, favourite food haunts include the Town Bar and Grill and Cliff Town House, as well as local organic fish restaurant Cavistons in Dalkey. In Eze-sur-Mer, it's everyone down to Club 55 in St Tropez for grilled fish.
She may be insistent that airports are the only place she gets time to shop, but Hewson boasts an enviable wardrobe by any standards. Since the homespun togs of her youth, Hewson's style has evolved, something she says comes from becoming a mother and more comfortable in herself.
Black has always been a staple, but the understated chic comes courtesy of some heavyweight names such as Dolce and Gabbana, Helmut Lang, Prada and Balenciaga. Like Madonna, Hewson is a big fan of Rogan jeans and can count the designer as a friend, ditto another of her favourites, John Rocha.
Of course, she also sports her own 'anti-bling' range, Edun, and fits into the sample size thanks to a healthy wheat-free diet, keen interest in homeopathy and regular yoga sessions, though a knee injury has made her give up on the more intensive Ashtanga form of the discipline.
By and large, Hewson's friends are Bono's friends and the group, which includes singer Gavin Friday, Simon Carmody and director Jim Sheridan and artist Guggi, is long established and not easily penetrated. Her closest friend is Larry Mullen's partner of 30 years, Ann Acheson, who also went to the same school.
"I would never talk about Ali's personal life, and you'll have a hard time finding one of her friends that will," says one pal who has been friends with the couple for well over a decade. "She's very private and the people who know her know and respect that."
One friend who admits responsibility for thrusting her publicity-shy pal into the limelight is campaigner Adi Roche. The founder of the Chernobyl Children's Project persuaded Hewson to visit Belarus in 1993 and work on Oscar-winning documentary 'Black Wind, White Land: Living With Chernobyl'.
Roche says: "Ali was a very quiet mother-of-two at the time I was trying to make the documentary. I tried to get hold of her for ages and eventually she agreed to meet me in Dublin."
She pays tribute to the " Trojan work" by Hewson, who has since made more than 10 aid trips to the region, helping raise millions of euro. Hewson later became godmother to Anna Gabriel, now 18, one of the first children to be brought from the disaster zone 15 years ago and adopted in Ireland.
First-hand experience of the devastation at Chernobyl saw her turn her attentions to the threat of Sellafield, spearheading a Â¤1.2m postcard protest demanding the British government close the facility, though without the desired response.
Her altruism sparked rumours of a presidency bid, but Hewson ruled herself on the basis that she can't speak Irish and Bono could never live in a smaller house. More likely, she felt the limelight that comes with the job would just be too much to deal with because, even though she put herself in the public eye to save other children with her charity work, her own children remain her primary concern.
Once asked in an interview why he never talked about his kids, Bono replied that he was under strict instructions not to. "My wife, Ali, is pretty private and she tries to keep all this away from them," he explained. "She's concerned about them I suppose. But I would love to talk about them."
As mild-mannered and warm as everyone says Hewson is, she's a lioness when it comes to her kids. "It's a well-known rule with her that you don't ask about the family," says one reporter. "She's perfectly friendly, but as soon as you start down that road the shutters go down and the interview is over."
It's well documented that her passport gives her occupation as 'Mother', although she has help at home, with nannies and tutors, when required, to help the household run smoothly, particularly when Bono's away. But she's been determined to make sure Jordan (22), Memphis Eve (20), Elijah (12) and John (10) live as normal a life as possible.
The girls went to State school St Andrew's in Blackrock, while the two boys are still at primary school. She says: "Although they have so much more than myself and Bono did while growing up, we definitely don't spoil them." To that end, they took their children to townships in Africa to drive home first hand how lucky they are.
After dedicating such energy to shielding her brood from the public gaze, it's no wonder Hewson was less than enthusiastic when her second eldest came to her with plans to go into acting.
"I said don't do it," she admits frankly of Memphis Eve, who has since stared alongside Sean Penn in 'This Must Be The Place' and briefly dated James Lafferty of ' One Tree Hill'. "No mother really wants that. It's hard if you're in a band like her dad, you have four or five in a group. But when you're on your own, you're taking on others' personalities and you're vulnerable to the whims of editors, directors and producers." he's supporting her daughter, but woe betide the director that would dare to take advantage.
In 2005, Hewson launched the ethical fashion range Edun. The wider notion behind the range was to encourage trade, rather than aid, in Africa, but the real impetus was Hewson's maternal concern that someone else's child could be making clothes for her own children.
Media used to launch the range made it clear that she hadn't got any more comfortable with being a public figure. In one US TV interview, Bono takes the lead but tries to explain that the brand is his wife's project to promote. He refers to her as 'lead guitar' in the operation, but she replies she'd rather be in the back on drums.
She often hides behind a wave of jet black hair, but it would be unwise to mistake publicity shyness with being weak.
A savvy businesswoman, she's not averse to making difficult decisions. Edun was floundering, haemorrhaging money poured into it by Hewson, so in 2009 she agreed to sell a 49pc stake to corporate luxury goods giants LVMH (which also owns a 70pc stake in her Nude make-up range), and moved elements of production to more efficient factories in China.
To get things done, she likes to do them herself. A few years ago, a pop-up shop for the brand was set up in Dublin. Customers calling in would have seen the wife of one of the most famous singers in the world organising the rails, chatting to customers and manning the tills.
Those who work with her on Nude are unequivocal about the extent of her input. "She is very, very heavily involved in the brand," said one member of the team. The range was set up 2007 and has won the highest ever accolade in the 'Anti-Ageing Beauty Bible' for its Replenishing Night Oil.
Hewson's passion for the brand insured claws were drawn when Stella McCartney dared to call a perfume Nude back in 2009.
Those close to the couple suggest Hewson has a major hand in the running of the family's investments which, aside from Nude and Edun, include property, a hotel, a stake in 'Forbes' magazine, Â¤688m worth of shares in Facebook and a wealth of business dealings tied in with Bono's billion-dollar private equity fund, Elevation Partners.
She's also the brains of the operation when it comes to the day-to-day running of the family and the long-term success of the couple.
U2 biographer Eamon Dunphy memorably stated "the best thing about Bono is Ali". And many would tend to agree. "Bono's famously a nightmare after he comes off a tour," says one source close to the couple. "He's a child at heart and if Ali wasn't there he'd be out every night. She can talk him down and keep him focused."
Every year, the family goes to the St Stephen's Day races at Leopardstown, with Hewson marshalling them out on to the stands for photos before sending down Champagne to the waiting snappers and journalists.
She's sure of herself and has never worried about losing Bono to another woman. She once said: "I don't feel threatened. You can live your life being scared of losing someone and, at the end of the day, if he is going to leave you, he'll leave you and that's it."
Friends maintain theirs is one of the strongest marriages in showbiz and that the canoodling so often snapped by paparazzi through restaurant windows and on walks is 100pc genuine.
For his part, Bono seems to know how lucky he is and that, in this group at least, he's not the star player. He said: "I feel our relationship has changed a lot. For a while I thought I was in charge. I was the hunter-protector. A few years ago it became clear somebody else was in charge and I feel I hold on a lot tighter to her than she does to me, and that slightly bothers me.
"She's so independent and sometimes I wish she wasn't."