He studied at Saint. Francis' College, Lucknow for a few years and then moved to his home Punjab, the place of his ancestors, in 1985. He studied at The Punjab Public School, Nabha and at Bikram College, Punjabi University, Patiala.
Sheirgill started his acting career in 1996 with the critically acclaimed film Maachis, directed by Gulzar, based on the terrorism in Punjab. The film did reasonably well at the box office and got him noticed by all the top filmmakers in the industry, which led him to being cast in Aditya Chopra's Mohabbatein alongside stalwarts like Amitabh Bachchan, Shah Rukh Khan, and Aishwarya Rai. He has consistently won rave reviews for all his performances in films such as Mere Yaar Ki Shaadi Hai (2002), Haasil (2003), Munna Bhai MBBS (2003), Yahaan (2005), Lage Raho Munnabhai (2006), Eklavya: The Royal Guard (2007), A Wednesday (2008), My Name is Khan (2010), Tanu Weds Manu (2011), Saheb, Biwi Aur Gangster (2011), Saheb, Biwi Aur Gangster Returns (2013), Special 26 (2013), Bullett Raja (2013), Fugly (2014) and Tanu Weds Manu Returns (2015). He also worked with rising star of the time Amisha Patel in Yeh Zindagi Ka Safar (2001). He won the Star Guild Awards previously known as Apsara guild awards for Best Actor In A Supporting Role for a movie A Wednesday!
Sheirgill married his long time girlfriend Priyanka in 2001. They have a son named Veer.
He started acting in Punjabi Films in 2005 with Manmohan Singh's Yaaran Naal Baharan, which did well at the box office. He went on to act in several other Punjabi films. He is currently one of the top actors in the industry, and some of the films he has acted in have been hits. He plans to produce and act in one Punjabi film every year, for which he has signed a deal with Bollywood production house Eros International. His first film as a Producer, Dharti, released in 2011 and did well at the box office. The next production from his company was Taur Mittran Di, that was released in May 2012. He has lined up two more films for production; the multi-star cast Saadi Love Story, in which he's cast Diljit Dosanjh, Amrinder Gill, Neetu Singh, Surveen Chawla and himself in a cameo and another film titled Rangeelay, which casts him in the lead with Neha Dhupia.