Thomas MacGregor-Robertson was born on 22 July 1887, the son of Joseph McGregor-Robertson MA, MB, FRSE and Isabella Williamson Seath McGregor-Robertson of Glasgow. After time in HMS ALBION and HMS ILLUSTRIOUS, he joined submarines as a Sub Lieutenant in August 1908.

In January 1909, he joined HMS C21 as First Lieutenant and, after promotion to Lieutenant, in April 1910, and time in the cruiser HMS ACHILLES, he joined HMS C17 as Commanding Officer in September 1913. McGregor-Robertson was next appointed in command of HMS E36 in late 1916 in build and the submarine was commissioned in November 1916.

E36 is believed to have been hit, whilst dived, by HMS E43 on Friday 19 January 1917. E43 was damaged in the incident, but made it back to harbour. E36 was lost with all hands. Thomas McGregor-Robertson is commemorated on the Portsmouth Naval War Memorial on Panel No. 24.