Career
He represented Glengarry in the Legislative Assembly of Ontario from 1926 to 1929 and in the Canadian House of Commons from 1930 to 1935 as a Conservative member. He was born in Williamstown, Ontario, the son of Hugh McGillis, and was educated there. He was also a livestock dealer.
McGillis was an unsuccessful candidate for a seat in the federal parliament in 1925.
He was defeated in 1929 by James Alexander Sangster for a seat in the provincial assembly but was elected to the House of Commons the following year. He was defeated by John David MacRae in the 1935 federal election.