After matriculating from the Edwardes College in Peshawar, he joined in the Pakistan Air Force in 1956, passing out in 1957 where he gained commissioned as a Pilot Officer. Further training took place in the United States where Flying Officer qualified to fly the F-104 Starfighter and participated in the second war with India in 1965. Flight-Lieutenant Hakimullah, with speed of Mach 1.1, notably intercepted the Indian Air Force's Folland Gnat flown by then-Flight lieutenant Brijpal Singh Sikand, who was forced to land near at the airstrip in Pasrur, Pakistan. This claim, however, has been contested by India. In 1971, Wing-Commander Hakimullah flew Mirage-IIIA in the western front of the third war with India, seeing aerial actions against the MiG-21.