Miraz was born in Khulna and grew up in Khalishpur of Khulna city and started playing cricket when he was 8. He went to Kashipur Cricket Academy from where he was first selected for the under 14 National Cricket Tournament. On 15 March 2019, along with several members of the Bangladesh test team, he was moments from entering the Al Noor mosque in Christchurch, New Zealand when a terrorist attack began. All members of the team were "deeply affected". Miraz decided to marry his long-time fiancée Rabeya Akhter Priti on 21 March 2019 in order to overcome the shock of the "terror attack".
Mehidy had a dream debut series as a Test player. After the remarkable 2016 Under-19 Cricket World Cup there was never any doubt in the team management's mind that they had found themselves an exceptional talent - in fact, in an echo of Australia's unveiling of Shane Warne on the 1993 Ashes tour. He was expected to debut a month ago for Afghanistan ODIs but was deliberately omitted to keep him as a secret from England. On 20 October 2016, Mehidy made his Test debut against England. Even though he is an off break bowler, he opened the bowling in his maiden Test innings. Ben Duckett, another debutant in the same Test match, became Mehidy's first Test wicket. In the same match he also became the seventh and youngest Bangladesh player to take a five-wicket haul on debut in a Test. In his 2nd Test match he became the sixth bowler to take three five-for in his first two Tests and took 19 wickets in the Test series and became the 9th player overall and 1st from Bangladesh to win the man-of-the-series award in debut Test series. Even though he had a horrible series as a batsman scored only 5 runs in 4 innings at an average of 1.25, Mushfiqur Rahim lauded the performances of the 19-year-old, and insisted Mehidy still has much more to offer. He said " Mehidyi is a good batsman also. He didn't show that now, but hopefully in future he will be a great all-rounder for Bangladesh". For his sensational debut series against England a new house from Bangladesh's prime minister was gifted to him. In November 2018, in the second Test against the West Indies, Hasan took the best match figures by a Bangladesh bowler in Tests, finishing with twelve wickets for 117 runs.
In December 2016 he was named in Bangladesh's One Day International squad for their series against New Zealand, although he did not play. In March 2017, he was added to Bangladesh's ODI squad for their series against Sri Lanka. He made his ODI debut in the first match of the series on 25 March 2017 at Rangiri Dambulla International Stadium. He took his maiden ODI wicket by dismissing Kusal Mendis for 4 runs. By the end of the match, he had picked up 2 wickets for just 43 runs in his quota of 10 overs – his second wicket being Dinesh Chandimal. He surprised everyone with his magnificent bowling. Many said, "He didn't look like a bowler bowling in his first match." He picked 4–29 in 3rd odi vs West Indies in 2018 and helped Bangladesh win series 2–1. In April 2019, he was named in Bangladesh's squad for the 2019 Cricket World Cup. He took 6 wickets and, at an economy rate of 5.08, was Bangladesh's most economical bowler at the tournament.
In April 2017, he was named in Bangladesh's Twenty20 International squad for their series against Sri Lanka. He made his T20I debut for Bangladesh against Sri Lanka on 6 April 2017. In April 2018, he was one of ten cricketers to be awarded a central contract by the Bangladesh Cricket Board ahead of the 2018 season.
