Answer by taking a quote from the following article:

Sir John Major  (born 29 March 1943) is a British politician who served as Prime Minister of the United Kingdom and Leader of the Conservative Party from 1990 to 1997. He served as Foreign Secretary and then Chancellor of the Exchequer in the Thatcher Government from 1989 to 1990, and was the Member of Parliament (MP) for Huntingdon from 1979 until his retirement in 2001. Since the death of Margaret Thatcher in 2013, Major has been the oldest living former Prime Minister. Born in St Helier, Surrey, Major grew up in Brixton.

Major was interested in politics from an early age. Encouraged by fellow Conservative Derek Stone, he started giving speeches on a soap-box in Brixton Market. He stood as a candidate for Lambeth London Borough Council at the age of 21 in 1964, and was elected in the Conservative landslide in 1968. While on the Council he was Chairman of the Housing Committee, being responsible for overseeing the building of several large council housing estates. He lost his seat in 1971.  Major was an active Young Conservative, and according to his biographer Anthony Seldon brought "youthful exuberance" to the Tories in Brixton, but was often in trouble with the professional agent Marion Standing. Also according to Seldon, the formative political influence on Major was Jean Kierans, a divorcee 13 years his elder, who became his political mentor and his lover, too. Seldon writes "She ... made Major smarten his appearance, groomed him politically, and made him more ambitious and worldly." Their relationship lasted from 1963 to sometime after 1968.  Major stood for election to Parliament in St Pancras North in both United Kingdom general elections in 1974, but was unsuccessful each time. In November 1976, Major was selected to be the candidate for the safe Conservative seat of Huntingdonshire. He won the seat in the 1979 general election. Following boundary changes, Major became the MP for the newly formed seat of Huntingdon in 1983, and retained the seat in 1987, 1992 and 1997. He retired from Parliament in 2001.  He was appointed as a Parliamentary Private Secretary in 1981, becoming an assistant whip in 1983. He was later made Under-Secretary of State for Social Security in 1985, before being promoted to become Minister of State in the same department in 1986, first attracting national media attention over cold weather payments to the elderly in January 1987, when Britain was in the depths of a severe winter.

Is there any major roles he had or he presented in his positions?
Following boundary changes, Major became the MP for the newly formed seat of Huntingdon in 1983,