Sangma was born on 1 September 1947 in Chapahati, a village in the erstwhile Garo Hills district of Assam (in present-day West Garo Hills, Meghalaya), to Dipchon Ch. Marak and Chimri A. Sangma as one of their seven children.[5] He lost his father when he was 11 and had to quit studies due to poverty. He was helped to return to school by a SalesianFather Giovanni Battista Busolin. Later, Sangma obtained a Bachelor of Arts degree from St. Anthony's College in Shillong before shifting to Dibrugarh in Assam, where he taught in the Don Bosco High School while pursuing Master of Arts in international politics from Dibrugarh University.[6]
Sangma married Soradini K. Sangma in 1973. They have two sons and two daughters together. Son Conrad serves as the Chief Minister of Meghalaya and daughter Agatha is the Member of Parliament from the Tura constituency.[7] Agatha was elected from Tura to the 15th Lok Sabha elections in 2009, and at 29, was the youngest minister in the UPA ministry.[8]
In 1973, Sangma became Vice-President of the Pradesh Youth Congress in Meghalaya and became the General Secretary of the party in 1975. He served in that position from 1975 to 1980.
In 1977, he was elected to the 6th Lok Sabha from Tura constituency in Meghalaya and represented the same constituency multiple times, from 1977-1988, 1991-2008, 2014-2016. The breaks in 1988 and 2008 were caused by his return to Meghalaya state politics. He became Speaker of Lok Sabha in 1996.
Sangma was expelled from the Congress on 20 May 1999, along with Sharad Pawar and Tariq Anwar, for raising the banner of revolt against Sonia Gandhi over the fact that she was a foreign-born citizen. Sangma along with Pawar and Anwar wanted a native-born citizen to be projected as the Prime Ministerial candidate.[11] After his departure from the Congress Party, he was one of the founders of the Nationalist Congress Party (NCP) along with Sharad Pawar and Tariq Anwar in 1999.[12] In January 2004, P.A. Sangma created a split in the NCP after Sharad Pawar became close to the NCP's former rival, Sonia Gandhi. After losing a battle for the NCP election symbol, Sangma later merged his faction with Mamata Banerjee's All India Trinamool Congress, forming the Nationalist Trinamool Congress .Sangma was one of two NTC MPs elected. He resigned from his Lok Sabha seat on 10 October 2005 as a member of AITC, and was re-elected as an NCP candidate in February 2006. He resigned from the 14th Lok Sabha for the second time in March 2008 to take part in the 2008 Meghalaya Legislative Assembly election.
Sangma's candidature for the 2012 presidential election was proposed by AIADMK and Biju Janta Dal, and later, supported by BJP as well. Sangma resigned from the NCP on 20 June 2012 after opposition from Sharad Pawar over his presidential candidature. Former Union Minister and a Congress tribal leader Arvind Netam also came out strongly in favour of the candidature of Sangma for the presidential post.[14][15][16]
On 22 July, Pranab Mukherjee was declared the victor over Sangma, crossing the half-way mark of 525,140 votes after votes in half the states had been tallied. While securing the required quota, Mukherjee secured 558,194 votes to Sangma's 239,966.[17][18] After the final results were published, Mukherjee secured 7,13,424 value of votes, while Sangma secured 3,17,032 values of votes. The Returning Officer for the election, and the Secretary General of the Rajya Sabha, Vivek Agnihotri, then declared Mukherjee to be elected as President of India. Sangma subsequently accused the President-elect of graft.[19]
1996-98 - Speaker of Lok Sabha -Chairman, (i) Business Advisory Committee; (ii) Rules Committee; (iii) General Purposes Committee; (iv) Standing Committee of the Conference of Presiding Officers of the Legislative Bodies in India; and (v) Institute of Constitutional and Parliamentary Studies;
President, (i) Indian Parliamentary Group, (ii) National Group of Inter-Parliamentary Union; and (iii) India Branch of the Commonwealth Parliamentary Association
1998 - Re-elected, Member of Parliament, Tura constituency, as member of Congress
1998 - Member, Committee on External Affairs and its Sub-Committee-I
1998 - Vice-President, Indian Institute of Public Administration
1998 - Member, Consultative Committee, Ministry of External Affairs
2004 - Member, Committee on External Affairs, Member, Committee on Private Members Bills and Resolutions, Member, Consultative Committee, Ministry of Home Affairs
2006 - Re-elected to Lok Sabha as N.C.P. candidate on 23.2.2006, Tura constituency