In 1730, he entered the Middle Temple, London, to read law, and in 1734 was called to the English bar.

In the meantime he had been admitted as a fellow-commoner to Trinity College, Cambridge, where in 1733 he received another master's degree in mathematics.

Prior to Belcher's arrival Nova Scotia had no formally trained law officers.

On July 28, 1755, he published a document which concluded that deportation of the Acadians was both authorized and required under the law.

He negotiated the peace that led to the Burying the Hatchet ceremony in Nova Scotia.