Sir David's biggest deals were the subject of fierce criticism
Sir David Freud, a government adviser on welfare reform, has quit to become a frontbench spokesman for the Conservatives.
It is the latest twist in a colourful career that has taken the great-grandson of psychoanalyst Sigmund from journalism to the City and now politics.
His involvement in raising £50bn ($72bn) during some of the biggest deals of the 1980s and 1990s made him a wealthy man - yet he continues to cycle to work, swim regularly in Hampstead Heath's ponds and conduct his business in functional off-the-peg suits.
But along the way the 59-year-old has proved a highly-controversial figure - as he candidly admitted in his own memoirs.
The first son of a chemical engineer who escaped Austria in 1938, Sir David has said he decided he wanted to be a journalist as an "extremely self-confident" 14-year-old public schoolboy in Croydon, Surrey.
His ambition before Oxford University was to work for the Guardian newspaper.
But instead he landed a job after graduating at the Financial Times, where his four-year stint on the Lex column schooled him in the world of business.
In 1983 he was headhunted by the firm Rowe & Pitman, which would change its name eight times during the 20 years he worked there.
His first job - writing research on companies from whom he was also soliciting money for advice - would be illegal today, and he told the Guardian in 2006 that the experience made him want to run a "very ethical sector".
Instead he moved into advising companies, and was involved in piecing together extremely complex deals such as the flotations of Eurotunnel and EuroDisney, which cost investors millions, and the financing of the Channel Tunnel rail link.
All earned him a great deal of publicity, as well as criticism.
Eurotunnel opened in May 1994 one year behind schedule and £2bn ($2.9bn) over budget.
Sir David later admitted the deal was a "shambles" and that he had "successfully sold the market a pup".
But his chutzpah meant his career was not held back.
Hauled before furious MPs to explain the mispricing of Railtrack, he was subsequently appointed an advisor to the government on its successor, Network Rail.
By 2003 he had risen to become vice-chairman of investment banking at the firm, by then named UBS.
But Sir David, who is married to a nurse and has three grown-up children, took early retirement aged 53, professing boredom with the City.
He remained active, however, serving as chief executive of the Portland Trust, which aims to attract investment to the West Bank and Gaza.
He also published his frank, witty memoirs, Freud in the City, which included a memorable account of the time he approached then Deputy Prime Minister John Prescott to admit that the Channel Tunnel rail link needed a £1.2bn ($1.7) taxpayer-funded bailout.
"So you're the banker?"
Suddenly I knew what to add.
The incident did his political connections no harm.
Sir David was hired by ex-Prime Minister Tony Blair to draw up a review of the welfare system, and in 2007 proposed opening up the system to the private sector as well as requiring lone parents to seek work earlier.
His suggestions were initially shelved amid reports of opposition from Gordon Brown, but he was hired again by Work and Pensions Secretary James Purnell in 2008 to work on a welfare green paper.
That paper called for measures to get more disabled people and lone parents into work, and was backed by the Conservatives while outraging many on the Labour left.
In response, the Tories promised a "full-blooded version" of Sir David's proposals, and criticised the government's implementation of them as "half-hearted".
Should the party form the next government, Sir David will now be in an even stronger position to make sure they are true to their word.