Born in Feni, Mohammad Saifuddin made his mark early, earning a spot in Bangladesh’s squad for the 2016 ICC U19 World Cup at home, just a year after making his First-Class debut for Chittagong Division. A seam-bowling allrounder, Saifuddin was one of the standout performers in the tournament, taking 13 wickets in six innings — the highest for Bangladesh — as the team finished third.

His journey to the senior side wasn’t without hurdles. He battled fitness concerns and was reported for a suspect bowling action. However, strong performances in the ACC Emerging Teams Cup for Bangladesh U-23 paved the way for his T20I debut in 2017 against Sri Lanka.

Later that year, he made his ODI debut on the tour of South Africa. Though his batting showed promise, his bowling proved expensive — most notably when he conceded five consecutive sixes to David Miller, who went on to equal the record for the fastest T20I century.

Despite initial struggles, Saifuddin earned a recall for the ODI series against Zimbabwe in October 2018. He made an immediate impact, rescuing Bangladesh with a 127-run stand alongside Imrul Kayes and notching his maiden ODI fifty. He followed that up with a Man of the Match performance in the next game, taking 3/45 in 10 overs.

Injuries, especially recurring back issues, have repeatedly interrupted his progress. Saifuddin picked up 13 wickets in seven matches at the 2019 World Cup but has not featured in ODIs since 2021. His T20I appearances have also been inconsistent, and after being dropped from the 2024 T20 World Cup squad, he took a brief break from the game.

After more than a year out of the national side, Saifuddin made his return in the T20I series against Sri Lanka in 2025, looking to rebuild his international career.