Riaz is the youngest child in his family. He has six sisters and a brother, Raisuddin Ahamed Siddique. He was brought up in CNB staff quarters of Faridpur for the first sixteen years of his life. His father, the late Zainuddin Ahamed Siddique, was a government service holder. His mother was Arjumand Ara Begum. His paternal home is in Jessore District. His father died in 1988.
Riaz participated in the examinations to be a pilot in the Bangladesh Air Force (BAF) right after his HSC results in 1988. He enrolled at the BAF Academy from 1989 to 1991 for flying training and to earn his bachelor’s degree under Rajshahi University in science, he was commissioned as a Pilot Officer and became a fighter pilot in Bangladesh Air Force in 1991. However, he was dismissed from the service for disobeying his superiors in 1993, he was promoted till Flying Officer rank.
After withdrawal from the BAF, Riaz moved to Dhaka in 1994. There he met his cousin, actress Bobita, and started his film career in 1995. Riaz married Mushfika Tina, a dance teacher, in a traditional Muslim wedding ceremony on 18 December 2007.