Career
He represented 2nd Kings in the Legislative Assembly of Prince Edward Island from 1872 to 1879 as a Conservative member. He was born in Saint Peters Bay, Prince Edward Island, the son of Dougald McIsaac, an Irish immigrant. McIsaac served on the Board of Works and was customs collector and controller of navigation laws for Portuguese Saint Peters.
McIsaac, who was also a justice of the peace and a commissioner for the probate of wills, was defeated when he ran for reelection in 1879.
He died in Head of Saint Peters Bay at the age of 80.