He joined the Bhartiya Janata Party in 1980. In 1986, he resigned from BJP after the party acted against his advice over an election petition.[5][6] He became a founding member of the Aam Aadmi Party after its formal launch in 2012, but resigned in 2015 after a disagreement with Arvind Kejriwal.[7] He later joined the organisation Swaraj Abhiyan and in 2016 became a founding member of its related political party Swaraj India.[8]
Bhushan represented Shaukat Hussain in 2008 for an appeal against his 10-year conviction for his role in the 2001 Indian Parliament attack.[12]
Bhushan appeared as senior counsel for Transparency International in the Provident Fund scandal case of Ghaziabad, which allegedly involved several judges of the Indian judiciary. The bench abandoned the hearing after deeming his remarks as contemptuous and termed his behavior as that of a street urchin.[13][14]
He represented V.S. Achuthanandan in the Supreme Court in the Idamalayar Dam corruption case against UDF leader R.Balakrishna Pillai and others. The bench awarded rigorous imprisonment for one year with fine of Rs. 10,000/- each to the accused persons.[17]
The father-son duo are currently[needs update] facing charges for contempt of court in Supreme Court of India for their statement about corruption in higher judiciary - specifically, about the corruption of former Chief Justices of the Supreme Court.[25]
During a hearing on the running case for contempt of court in November 2010, Shanti Bhushan went on to say, "The question of apology does not arise. I am prepared to go to jail."[26]
Shanti Bhushan was a prominent member of the core committee of India Against Corruption.[27] The first Lokpal Bill was passed in the 4th Lok Sabha in 1969, but did not pass through the Rajya Sabha.[28] Shanti Bhushan was a member of the Joint Drafting Committee for the Jan Lokpal Bill, constituted by the Government of India, representing the Civil Society.[29]