First elected to the House of Commons in 1970 as the Conservative MP for Bridgewater (1970-2001), Tom King went onto hold a number of positions when his party was in opposition between 1974 and 1979, most notably as Shadow Energy Secretary.
After the Conservatives returned to office following the 1979 general election, he served as a junior minister before being promoted to the Cabinet in 1983, as Minister of the Environment (January-October 1983). Then October 1983 King became Employment Minister (1983-85) and he was to remain in this post until September 1985.
As a result of a cabinet reshuffle he was then appointed as the Secretary of State for Northern Ireland (1985-89) .
He arrived in his new post at a difficult time given the fact that the British and Irish governments were just about to conclude the negotiations which were to end with the signing of the Anglo-Irish Agreement (AIA) in November 1985.
It was therefore to fall to King to try convince sceptical unionists about the merits of the AIA and given their level of opposition to it, this soon proved to be an impossible task. Not only did he fail to make any headway but some of the language he used in trying to achieve this goal, caused some anger amongst the authorities in Dublin.
In spite of these initial problems King took on the role as co-chairman of the ministerial conference established under the AIA and over the next four years was to be the senior British government minister responsible for its operation. As in other areas his achievements in this whole area was to be mixed. To begin with he was able to withstand the early unionist backlash against the AIA and refused to agree to their demands for it to be suspended as the price of them entering a new round of political talks. At the same time however King's ongoing attempts to win them round to the AIA failed and left a growing sense of alienation amongst many with this vacuum being filled by loyalist paramilitaries. As for nationalist opinion, both north and south, doubts remained about his fundamental support for the AIA. If anything this intensified as some of the grievances they had expected the AIA to address seemed to be effectively blocked by him and the British government.
In 1989 King's term of office in Northern Ireland was to end when he was made Defence Minister (1989-92) and after the general election of 1992 he returned to the backbenches where he was to remain a loyal supporter of the Conservative government. He announced his intention to retire as an MP prior to the 2001 election and in June 2001 was awarded with a life peerage, taking his seat in the House of Lords as Lord King of Bridgewater.