Jahangir Tareen began his political career in 2002 after he was elected as the member of the provincial Assembly of Pakistan in Pakistani general elections, 2002 representing Rahim Yar Khan on the ticket of Pakistan Muslim League (Q)
He served as special adviser on agriculture and social sector initiatives to then chief minister of Punjab Chaudhry Pervaiz Elahi. In August 2004, he was inducted into federal cabinet, after being elected MNA from NA 195 and was made Federal Minister for Industries and Production in Shaukat Aziz’s cabinet where he remained until 2007.
In Pakistani general election, 2008, Tareen was re-elected as the member of the National Assembly for the second time from Constituency NA-195 on the ticket of Pakistan Muslim League (F). He was the parliamentary leader of PML-F in the National Assembly. Later, he formed a separate faction of parliamentarians, called "Tareen's group". At the start of 2011, he showed intent to launch his own political party consisting of politicians free from corruption charges, but later in November 2011, he joined Pakistan Tehreek-e-Insaf along with a number of associates saying that his vision was similar to PTI.
In September 2013, Imran Khan appointed Jahangir Tareen as the Secretary General of Pakistan Tehreek-e-Insaf to replace the previous Secretary General Pervaiz Khattak, who became the Chief Minister of Khyber Pakhtunkhwa after the Pakistani general election, 2013.
In August 2015, he retained its membership in the National Assembly after commission of Punjab election tribunal announced its verdict in favour of Tareen over a petition filed by the former secretary general of Pakistan Tehreek-i-Insaf (PTI) against alleged rigging in constituency Lodhran during the 2013 elections.