Mr Clarke has a reputation for tough talking
Although he has only been an MP since 1997, Charles Clarke has been close to the heart of power in the Labour Party since the 1980s.
The son of a senior servant, Mr Clarke was privately educated at Highgate School before going on to Cambridge where he studied maths and economics.
He was Neil Kinnock's chief-of-staff from 1983 to 1992 and had a hand in the former party leader's conference speech attacking the Militant wing's administration of Liverpool.
Before that, he had served as president of the National Union of Students, a well-trodden path to the "grown-up" world of Labour politics at Westminster.
Later, as Labour's party chairman, Mr Clarke proved his loyalty to New Labour, by ruffling feathers within party and union ranks.
He has a reputation as a tough-talking political "bruiser" - which was not diminished by his time as education secretary, between 2002 and 2004.
He pushed the Higher Education Bill - with its controversial plans for variable tuition fees - through the Commons in the face of widespread Labour backbench opposition.
He also pointedly snubbed the biggest teachers' union, the NUT, by declaring in 2003 that no education ministers would attend its annual conference.
Delegates had "seriously damaged" the image of the teaching profession, he said, and he again turned down an invitation to speak at the union's conference this year.
THE HOME OFFICE
The Home Office employs almost 70,000 people across England and Wales
Its remit includes crime, policing and justice, drugs, terrorism, immigration, community and race relations
The department also collects statistics in areas like crime and immigration
It carries out scientific projects to support its work - eg, looking at biometrics for ID cards
Mr Clarke - who is married with two sons - was tipped for office from the moment he was elected as MP for Norwich South in 1997, despite a few off-message wobbles.
He made clear his opposition to cuts in lone-parent benefits (although he supported it in the voting lobbies) and he called for a fully elected second chamber.
After a year at the education department, he became a minister of state at the home office before the 2001 general election.
But he only gained high public prominence when he was moved to the newly created post of Labour chairman, with his salary paid from party funds.
This caused great controversy, since constitutionally Labour already had its own elected party chairman.
In the role he often served as a general media trouble-shooter for the party.
But he has also exhibited a tendency for straight talking which has proved too blunt for some at times.
He accused Prince Charles of being "old fashioned and out of time" for views he expressed on the education system.
Mr Clarke's appointment as Home Secretary puts him in charge of the government's top priority - security.
And he has already indicated that he intends to carry on with Mr Blunkett's policies on national ID cards and his uncompromising stance on asylum and immigration, saying: "There will be continuity between David's approach and mine."