商法
On returning from the United States, Donovan became a Reader in Law at the University of Adelaide. In 1952, he was appointed Chair of Commercial Law at Melbourne University by his friend Zelman Cowen, who would later serve as 19th Governor General of Australia. During this time, he was a visiting professor at Columbia Law School and was President of the Melbourne University Staff Association. In 1953, the University granted him a Master of Laws degree. Whilst at Melbourne, Donovan published key case books for Australian Commercial law, and one publication 'Signed, Sealed, and Delivered: An Introduction to Australian Commercial Principles' was printed six times. Throughout his life he was also a Barrister of the Supreme Courts of Victoria and Queensland.