He was bought by Kolkata Knight Riders for the 2009 Indian Premier League; although KKR paid US$600,000 for Mortaza, he played just one match for them, in which he went for 58 runs in 4 overs. Due to his international commitments, Mortaza has infrequently played for Khulna Division in Bangladesh's domestic cricket competitions. While he has represented Bangladesh 36 times in Tests and in 100 ODIs between 2001 and 2005 he played only 11 first-class and 9 list A matches for Khulna Division in the same period. In 2012 he joined the Dhaka Gladiators and 2015 from Comilla Victorians in the newly formed Bangladesh Premier League twenty20 competition and captained them to the tournament title and led Comilla Victorians clinched the title of the third 3rd Bangladesh Premier League (BPL) as well as champion of 2017 Bangladesh Premier League fourth time as captain.This time he played for Rangpur Riders.

In March 2018, Mortaza took four wickets in four balls bowling for Abahani Limited against Agrani Bank Cricket Club in the 2017–18 Dhaka Premier Division Cricket League. He took his first List A hat-trick and became the first Bangladeshi bowler to take four wickets in four balls in List A cricket. He finished the 2017–18 Dhaka Premier Division Cricket League as the leading wicket-taker of the tournament, with 39 dismissals in 16 matches.

Mortaza was born in the district of Narail in south-west Bangladesh. He enjoyed playing sports such as football and badminton from a young age, and sometimes went swimming in the nearby River Chitra instead of doing school work. He was admitted to the Department of Philosophy at the Jahangirnagar University in 2003–04 for his bachelor's degree.

Mortaza has been described as an open and animated character who enjoys motorcycling. He used to travel from a local bridge onto the tops of passing goods barges. He is very popular in his home town, leading to him being dubbed their "Prince of Hearts". At Govt. Victoria College