Haroun was recruited at a young age from Sudan by Qatar. He gained eligibility to represent Qatar in February 2015. His first recorded performance was a time of 45.74 seconds for the 400 m in Doha in April 2014, which placed him among the world's most promising young sprinters for the event. He announced himself on the elite scene in his next performance at the XL Galan in February 2015 by running an Asian indoor record of 45.39 seconds, which was also the third fastest ever by a junior category athlete and the fastest ever indoor debut. His next outing one month later he set an outdoor best of 44.68 seconds. He was a comfortable victor at the 2015 Arab Athletics Championships in April, beating Egypt's Anas Beshr by nearly a second.