He joined the Indian Army in June 1963 after graduating fromthe National Defence Academy and Indian Military Academy before resigning inearly 1965. He rejoined the Army again as hostilities broke out with Pakistanand served as Captain in the 1965 Indo-Pakistan War.
He was inducted into the Congress by Rajiv Gandhi, who washis friend from school and was first elected to the Lok Sabha in 1980. In 1984,he resigned from Parliament and from Congress as a protest against the Armyaction during Operation Blue Star. Subsequently he joined the Shiromani AkaliDal was elected to the state legislature from Talwandi Sabo and became aminister in the state government for Agriculture, Forest, Development andPanchayats.
In 1992 he broke away from the Akali Dal and formed asplinter group named Shiromani Akali Dal (Panthic) which later merged with theCongress in 1998 after Sonia Gandhi took over the reign of the party. He servedas the President of Punjab Pradesh Congress Committee on two occasions from1999 to 2002 and 2010 to 2013, he also became Chief Minister of Punjab in 2002and continued until 2007.
In September 2008, a special committee of Punjab VidhanSabha expelled him on the count of regularities in the transfer of land relatedto the Amritsar Improvement Trust by the Akali Dal-Bharatiya Janata Party ledgovernment. In 2010, the Supreme Court of India held his expulsionunconstitutional on the grounds it was excessive and unconstitutional.
He was appointed as chairman of Punjab Congress CampaignCommittee in 2008. Captain Amarinder Singh is also a Permanent Invitee to theCongress Working Committee since 2013. He defeated senior BJP leader ArunJaitley by a margin of more than 1,02,000 votes in 2014 general elections. Hehas been a member of the Punjab Vidhan Sabha for five terms representingPatiala (Urban) thrice, Samana and Talwandi Sabo once each.
On 27 November 2015, Amarinder Singh was appointed Presidentof Punjab Congress in the run up to Punjab elections slated for 2017.
President of All India Jat Maha Sabha
Capt. Amarinder Singh is president of the All India Jat MahaSabha. He had been associated with the Jat Maha Sabha for last 30 years as itspatron since 1980 when Capt. Bhagwan Singh was its president.