Former basketball player and Arjuna awardee Sajjan Singh Cheema rejoined the Aam Aadmi Party (AAP) on Monday.
Mr Cheema had left the AAP to join the SAD in 2019.
AAP's Punjab unit chief Bhagwant Mann and state affairs in-charge Jarnail Singh welcomed him into the party fold.
"Every section of Punjab is joining the Aam Aadmi Party as it is a people's party aimed at serving the people of the country," Mr Mann said on the occasion.
The people of Punjab want a change in politics and only the AAP is capable of doing it, Mr Cheema said on joining the party.
He added that he was influenced by the "pro-people" policies of the Arvind Kejriwal government in Delhi and decided to return to the party.
Mr Cheema had unsuccessfully contested on an AAP ticket from the Sultanpur Lodhi seat in the 2017 assembly polls.