Bonthrone managed the Dons from 1971 until his resignation in 1975.[3][5] The club won the Drybrough Cup in 1971 just after he was appointed.[3][6] He gave Willie Miller his debut, but had to contend with the high-profile departures of Martin Buchan and Joe Harper,[5][6] which effectively broke up the team that had been successful under Turnbull.[5][4]
After leaving Aberdeen, he became commercial manager with East Fife before retiring.[5][6]