Jim Wallace has been a constant factor in Scottish politics since the advent of devolved government.
Jim Wallace was triumphant after the general election last week
The 50-year-old has worked with three first ministers, Donald Dewar, Henry McLeish and Jack McConnell.
He has also held the top post three times when sickness, death and scandal befell the Labour incumbent.
Mr Wallace entered elected politics at 29 as MP for Orkney and Shetland and on becoming an MSP in 1999 he accepted the post of deputy first minister.
Born and raised in Dumfriesshire, the father-of-two was bitten by the political bug when at the age of nine.
He collected autographs from visiting politicians and to this day he still has one from Tam Dalyell.
Mr Wallace, who joined the Liberal Party in 1972 and became its Scottish party leader in 1992, studied at Downing College, Cambridge and went on to do his LLB legal qualification at Edinburgh University.
For a number of years he worked as an advocate, but his chief ambition was to become a member of parliament.
He stood for the European Parliament in 1979 and contested the Westminster seat of Dumfriesshire in the same year, without luck in either contest.
When he failed to become elected on his doorstep, he went on the search for a seat in the far north of Scotland.
The 1983 General Election proved to be his year when he won the Orkney and Shetland seat, replacing veteran Liberal MP Jo Grimond.
The Church of Scotland elder diligently served the constituency for almost 20 years at Westminster.
The Liberal Democrat from Dumfriesshire became an elected MP at 29
In 1999, as the new MSP for Orkney, Mr Wallace's career took a turn which would place him in a power-broking role he could only have dreamed of.
When no clear winner emerged in the first devolved government, Mr Wallace's Liberal Democrats agreed to become Labour's coalition partner.
That deal resulted in Mr Wallace becoming deputy first minister and justice minister in the first executive cabinet.
He credits his party's role in the coalition for bringing about policies such as the scrapping of upfront tuition fees and free personal care for the elderly.
As justice minister in the first administration he saw through another cherished Lib Dem goal, land reform.
Less than a year after devolution, Mr Wallace took up the post of first minister when Donald Dewar became ill.
He stepped in again when Mr Dewar died in October 2000.
Henry McLeish took back the reins for Labour when he was elected to succeed Mr Dewar.
When Mr McLeish quit over the "Officegate" debacle in 2001, Mr Wallace found himself, albeit briefly, back in the hot seat.
That year, Mr Wallace was named Scottish Politician of the Year in a media poll.
The 2003 Holyrood elections again saw no party gain an overall majority - a state of affairs virtually guaranteed by the voting system that the Liberal Democrats had negotiated in the wilderness years.
Again a coalition was formed, but this time round Mr Wallace was made enterprise minister, a role in which he seemed far less comfortable than the justice slot.
Jim Wallace promoting the G8 tartan
Tensions between Labour and the Liberal Democrats had never been far from the surface, with Labour irked at what it saw as the Lib Dems' soft stance on law and order, and many in Labour ranks horrified by the Lib Dems' demand for proportional representation in local government.
The Lib Dems, in turn, found the relationship far from easy, with particular irritation in their ranks over the necessity, or otherwise, of putting west coast ferry services out to tender.
Mr Wallace's resignation announcement followed a successful 2005 general election for the Lib Dems on both sides of the border.
When the results came in, a triumphant Mr Wallace claimed: "Across Scotland we increased our share of the vote by more than 6%.
"For the first time in over 80 years, the Liberal Democrats are clearly Scotland's second party, both in terms of seats and in terms of votes."