A self-confessed "stern disciplinarian" said to have earned the nickname "Thrasher" at school, Andrew Mitchell was installed as the government's chief whip in the recent reshuffle.
The 56-year-old Tory is noted for his ambition, and admits to having a "competitive streak" - though he insists he is not "ruthless".
Mitchell was educated at the prestigious Rugby public school and Cambridge University, before joining the army and serving as a UN peacekeeper during the 1970s.
He went on to forge a lucrative career in banking, but was always determined to enter politics.
The MP outside the Downing Street gate where the incident is said to have occured
While a child in Hampshire his father Sir David was elected as a Conservative MP and served as a minister under Margaret Thatcher.
The father and son's time in the House of Commons coincided for a decade after the younger Mitchell became MP for Gedling, Nottinghamshire in 1987.
Mitchell was made vice-chairman of the Conservative Party under John Major, and was a government Whip during the notorious rebellion over the Maastricht Treaty.
Later promoted to social security minister, he suffered a setback in losing his seat during the Labour landslide of 1997.
However, within four years he had made it back to Westminster, representing Sutton Coldfield.
Now viewed as a Cameron loyalist, just seven years ago he was once a fierce opponent, running David Davis's campaign in the contest for the Tory leadership.
As International Development Secretary in May 2010 he was committed to enshrining in law an obligation on the UK to spend 0.7% of national income on overseas aid, a move that has not always proved popular with Tory backbenchers.