Jamal Nazrul Islam was born on 24 February 1939 in Jhenaidah. His ancestral home is at Jujkhola Narayanhat of Fatikchhari Upazila of Chittagong District, East Bengal. His father, Khan Bahadur Sirajul Islam, was a sub-judge in British India. Because of his father's job, Islam spent his early school years in Calcutta. He studied at Chittagong Collegiate School and College until ninth grade and then he went to Lawrence College, Murree in West Pakistan to pass the Senior Cambridge and Higher Senior Cambridge exams. He received a BSc degree from St. Xavier's College at the University of Calcutta. In 1959, he got his Honors in Functional Mathematics and Theoretical Physics from Cambridge University. He completed his master's degree in 1960. As a student of the Trinity College, he finished the Mathematical Tripos. Islam obtained his PhD in applied mathematics and theoretical physics from Trinity College, Cambridge in 1968, followed by a DSc in 1982.