Shadman Islam is a left-handed top-order batter. Cricket runs in his blood as his father Shahidul Islam was one of the prominent members of his team at the school level. Being a regular member of the Bangladesh U-19 team, Islam had an outstanding U-19 World Cup in 2014 where he topped the run-charts, scoring 406 runs at a mammoth average of 101.50 which included one century and two half-centuries.

Islam's dream run started in the domestic cricket from the 2017–18 Bangladesh Cricket League and the smooth flow of runs continued from the southpaw's bat. After smashing 648 runs in six games in the 2018-19 National Cricket League, the 23-year old was finally successful in grabbing the selector's attention. In November 2018, Islam was named in Bangladesh's Test squad for the series against West Indies and made his debut in whites during the 2nd Test at his home ground, Dhaka. Shadman quickly repaid the faith shown in him as he scored a gritty knock of 76 from 199 deliveries. A couple of months later, he toured New Zealand with the Test squad and adapted to the alien conditions reasonably well. However, he got good starts, but he failed to make big scores. In a short period, Shadman impressed with his compact technique and emerged as a handy choice to open with Tamim Iqbal. In 2021, in a one-off Test against Zimbabwe, he scored his maiden Test hundred, making an unbeaten 115 runs in the second innings. He made his mark as a specific red-ball batter and also played a crucial role in the historic 2-0 Test series win against Pakistan in 2024.