The Top Gun star spent hours meeting fans at the premiere of his new film in London's Leicester Square.
Jack Reacher is based on One Shot - one of the series of best-selling novels by Lee Child about the eponymous former soldier turned drifter who travels the United States dealing out his own brand of justice.
Tom said: "It was easy, it was just a great character to play.
"That's kind of my life actually you know, making movies I'm here in London for four months and I shoot in Pittsburgh, Baton Rouge and Italy. I spend that kind of life making movies."
Child - real name Jim Grant - said he knew Tom was the right man for the role when he saw him carry on with work on set despite a serious hand injury.
The author, who was born in Coventry and grew up in Birmingham, said: "He's reckless like Reacher."
Tom's co-star Rosamund Pike said she loved working with the man she described as "the greatest movie star of my lifetime".
She said: "I was on my stomach watching Top Gun aged 12, 13 and it was very exciting to work with a guy who is still on top of his game, and into the room walks the man who created all those iconic parts and he doesn't disappoint on any level."