Career
Born in Castleknock, Ireland, the son of William Gwynne and Eliza Nelson, he emigrated to Canada in 1832. Gwynne was elected a bencher of the Law Society of Upper Canada in 1849 and appointed Queen's Counsel in 1850. In 1874, he was appointed a puisne judge of the Ontario Court of Appeal.
In 1879, he was appointed to the Supreme Court of Canada and he served until his death in 1902.