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.

Amir pleaded guilty on the verdict handed out by his prosecutor in the International Cricket Council, and publicly asked for forgiveness.

[11] 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 three months in prison.

His ban was considered lenient, due to his juvenile age and confession, as compared to the other two conspirators who were given seven and 10 years' suspensions, effectively ending their careers.

[12] 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.

[22] Amir was born on 13 April 1992 in Changa Bangial, Gujar Khan, Punjab, Pakistan into a Punjabi Muslim family.

The second youngest of seven children, consisting of six sons and a daughter, his father Raja Mohammad Fayyaz served in the Pakistan Army before taking a government job as a watchman in a school.

In this tri-nation tournament played in Sri Lanka he again excelled with his speed and swing bowling taking 9 wickets at an average of 11.22 in three matches.

[10] In March 2008, he made his domestic debut for the Rawalpindi Rams whilst concurrently representing the National Bank of Pakistan.

He took the wicket of Ravi Bopara with only his second ball, with Shoaib Malik taking a fine catch, and conceded only one run in his debut international over.

Amir made his One Day International match debut against Sri Lanka taking 3 wickets at an economy rate of 4.50 and also scoring 23 runs.

After his successful 2009 T20 World Cup tournament, Amir was selected in the test squad for Pakistan for the series in Sri Lanka.

[38] He was chosen alongside fast bowler Umar Gul and Abdur Rauf, ahead of more notable and experienced names such as Sohail Tanvir.

After five years, on 13 March 2015, Amir made his domestic comeback playing for Omar Associates in the grade II patron's trophy.

During the first two games against arch rivals India and South Africa, Amir failed to pick up wickets but was economical with the figures of 0/32 (8.1) and 0/50 (10) respectively.

Chasing Sri Lanka's target of 237, Pakistan was struggling at 162/7 before he arrived and, along with skipper Sarfraz Ahmed, shared an unbeaten stand of 75 to guide his team to their fourth semi final of their Champions Trophy.

Amir was pivotal in helping Pakistan win the 2017 ICC Champions Trophy by claiming top three wickets against arch-rivals India in the Final.

In his final Asia Cup game against India, Amir was trounced for 41 runs in his 5 overs without picking up a single wicket.

[70] On 24 March 2024, Amir reversed his decision to retire, and after "positive discussions" with the PCB, made himself available for selection ahead of the T20 World Cup scheduled for June that year.

[75][76] In August 2010, the English newspaper News of the World published allegations that Amir and fellow bowler Mohammad Asif deliberately bowled no-balls during Pakistan's 2010 tour of England in return for payment from a betting syndicate.

As a result of the allegations and video posted by News of the World, Scotland Yard announced during the evening that they had arrested Majeed on charges of suspicion of conspiracy to defraud bookmakers.

[82] On 2 September 2010, after the warm-up List A game between Pakistan and Somerset, the International Cricket Council announced that they had suspended Amir under the provisions of the ICC's Anti-Corruption Code.

In an article for the News of the World, Atherton asserted that Amir is an asset to the game and must not be given a harsh punishment, considering his immense talent and young age.

Atherton, now a journalist and broadcaster, recalled how Nasser Hussain, also an ex-England skipper, had summed up the mood at Lord's the previous Sunday: "Nasser Hussain, who I once saw walking around the team hotel in Sri Lanka in the early hours of the morning before a Test match unable to sleep, so worried was he about his form, spoke for us all when he said, 'Please don't let it be the kid'."

Atherton added: "The 'kid' in question was Mohammad Aamer, the young, good-looking and prodigiously-talented Pakistan bowler who had blown England away on the second morning at Lord's with a mesmeric spell of left-arm bowling and who now, we had been told, had overstepped the front line twice for a few dollars more.

"[84] Former South Africa bowler Henry Williams, called for Mohammad Amir to be treated with compassion if found guilty of spot fixing.

[90] Reports also emerged by Geo News that stated that Scotland Yard might call Amir, Mohammad Asif and Salman Butt back into the UK to complete the spot-fixing investigation[91] Amir's teammate Butt who was also implicated in the Spot-fixing scandal announced that he wanted a delay in his hearing because he wanted the Scotland Yard investigation to be completed first.

However Amir and Asif announced they were to go ahead with their trials as planned because they wanted a decision to be reached quickly so that they could be selected for the World Cup squad.

[97] Some former players around the world such as Michael Vaughan, Andrew Flintoff and Ian Healy called for Amir to be banned for life.

[102] Amir was later transferred to Portland Young Offenders Institute in Dorset, from which he was released on 1 February 2012, having served half of his six-month sentence.