Born in Woodstock, Canada West (now Ontario), the son of John W. Nesbitt and Mary Wallace, he was called to the Ontario Bar in 1881. A practising lawyer, he was appointed to the Supreme Court of Canada in 1903. He served for two years until he resigned in 1905.
In 1887, Wallace Nesbitt married Louisa Andrée Plumb née Elliott (d. 1894), the widow of his one-time law partner Thomas Street Plumb (d. 1885), and became the stepfather of two young children. In memory of his stepson Gentleman Cadet Douglas Burr Plumb, who drowned at Romaine, Labrador on June 22, 1903, Wallace Nesbitt donated a stained glass memorial window in 1920 featuring a Royal Military College of Canada crest and motto.[3]