He was the sheriff who rode in to clean up Ireland's financial Dodge City in 2010.
As Matthew Elderfield heads off into the sunset, he will look back on a career with more highs than lows which has left Ireland's financial sector almost unrecognisable.
Taking on Sean Quinn's then business empire in 2010 made the Englishman's reputation for toughness, proving him as the antidote to the previously lax approach to enforcement.
It was Mr Elderfield who took the decision to have Quinn Insurance put into administration after the company failed to rectify a solvency shortfall.
Despite pressure to soften his approach, Mr Elderfield, just months in the job and new to Ireland, saw the action on Mr Quinn as both necessary and as a signal of intent.
The intervening fall of the Quinn empire has softened the shock of the Quinn Insurance decision but at the time it was seen as momentous – a tangible break with the hands-off approach of previous regulators.
"It showed we were serious about supervision in Ireland," he said later in an interview.
The Quinn Group debacle has spun off in a thousand different directions since.
Mr Elderfield's action remains controversial along the Border, where support for the Quinn family remains formidable.
But, there is no doubt that it sent a shudder through the financial sector in Dublin too, a sign that light-touch regulation was finished.
Mr Elderfield beefed up his team of regulators quickly, and the posse has been busy ever since.
Last year, the Central Bank of Ireland hit financial firms with a record €8.49m of fines. That was up from €5m a year earlier.
The biggest single fine was €3.2m charged to Alico Life International, for breaching insurance regulations.
Aviva was hit with a €1.23m fine. Ulster Bank was fined €1.96m for regulatory breaches.
Also, last year and again under Mr Elderfield's watch, the country's oldest stockbrokers, Bloxham, was quickly shut after financial irregularities were uncovered at the firm.
It all marks a transformation from the cosy regimes of the past.
But there have been misses too, especially when Mr Elderfield, as regulator, tried to face down the big banks and their owners in the Department of Finance.
A warning to banks not to increase the interest they charge on variable-rate mortgages fell on deaf ears.
State-owned and private- sector banks have lifted rates with impunity.
Under Mr Elderfield's watch the mortgage crisis has been allowed to drift further and further out of control – even as he publicly demanded that banks address the issue.
That particular disaster has many parents, but as regulator Elderfield bears at least some of the responsibility.
That's true too of his bank "stress tests" in 2010. They failed to convince the markets that Irish banks were sound and a fresh, independent root- and-branch assessment of the banks was needed a year later.
The regulator also fell short when Ulster Bank customers were left locked out of their bank accounts for weeks last year because of a computer problem.
In the UK, Ulster's parent faces a hefty fine after enforcement action was launched yesterday.
No such action has begun here, even though Irish customers were the worst hit by the problem.