Amir made his first-class debut in November 2008, and his first One-Day International and Test appearances in July 2009 in Sri Lanka at the age of 17. He played his first international match during the 2009 ICC World Twenty20, where he played in every game, helping the national side win the tournament.[2][3]

On 29 August 2010, he was arrested for spot-fixing and was given a five-year ban for bowling two deliberate no-balls. Amir pleaded guilty on the verdict handed out by his prosecutor in the International Cricket Council, and publicly asked for forgiveness.[4] In November 2011, Amir was convicted at Southwark Crown Court, along with Salman Butt and Mohammad Asif, of conspiracy charges relating to spot-fixing and spent 3 months in prison. He was given a five-year ban which was considered lenient, due to his juvenile age and confession, as compared to the other two conspirators who were given 7 and 10 years' suspensions, effectively ending their careers.[5]

On 29 January 2015, it was announced that Amir would be allowed an early return to domestic cricket despite his original ban being due to expire on 2 September 2015.[6] Mohammad Amir signed  to play in the 2015 Bangladesh Premier League . He returned to play for Pakistan on their tour of New Zealand in 2016.

In August 2018, he was one of thirty-three players to be awarded a central contract for the 2018–19 season by the Pakistan Cricket Board (PCB). On 26 July 2019, he announced his retirement from Test cricket in order to focus on limited overs cricket.On 17 December 2020, he announced his retirement from international cricket.