He completed his postgraduate degree (LLB) at the University of the Witwatersrand in 1949, and returned to Rhodes as a lecturer in the department of law in 1955.
On 8 February 1993, in recognition of his services to the law of South Africa, State President FW de Klerk conferred on him letters patent, making Kerr then one of only eleven academic lawyers in South Africa to attain the honorary status of Senior Counsel.
He retired in 1990 but retained an office in the faculty, remaining its most prolific author until, in 2010, the 71st year of his association with the university, he was hospitalised for heart surgery.
"[2] Kerr's research interests embraced contract, agency, sale, lease and customary law.
These two works were later combined under the title The Customary Law of Immoveable Property and of Succession, which has run to three editions.