Iqbal was born on 23 December 1952 in Sylhet. His father, Faizur Rahman Ahmed was a police officer who was martyred in the Liberation War of Bangladesh. His mother was Ayesha Akhter Khatun. He spent his childhood in different parts of Bangladesh because of the transferring nature of his father's job. His elder brother was the legendary author and filmmaker Humayun Ahmed. His younger brother, Ahsan Habib, is the Editor of the satirical magazine, Unmad (Mad) and a Cartoonist. Iqbal and his siblings were encouraged to write by his father in their early lives.
Iqbal passed the SSC exam from Bogra Zilla School in 1968 and the HSC exam from Dhaka College in 1970. He earned his BSc in Physics from Dhaka University in 1976. He went to the University of Washington to obtain his PhD the same year and earned the degree in 1982.
He married Yasmeen Haque in 1978. She is currently the Dean of the Life Science Department and Professor of the Department of Physics at SUST. They have two children – son Nabil and daughter Yeshim.
After obtaining his PhD degree, Iqbal worked as a post-doctoral researcher at California Institute of Technology (Caltech) from 1983 to 1988. He then joined Bell Communications Research (Bellcore), a separate corporation from the Bell Labs (now Telcordia Technologies), as a research scientist. He left the institute in 1994.
Iqbal also serves as the Vice President of Bangladesh Mathematical Olympiad committee. Iqbal played a leading role in founding the Bangladesh Mathematical Olympiad and popularized mathematics among Bangladeshi youths at local and international level. In 2011 he won the Rotary SEED Award for his contribution in the field of education.
In support of the war crime trials carried out at the premises of the International Crimes Tribunal in Bangladesh, he participated and featured prominently at the 2013 Shahbag protests.
Iqbal survived a stabbing attack in the head on 3 March 2018 in a prize giving ceremony in Shahajalal University of Science and Technology in Sylhet. The attacker, a 25-year old male, was arrested after he was beaten by the students. The attacker claimed that he had tried to kill him because the attacker wrongly believed he was an "enemy of Islam". The attacker never read any book of Iqbal.
