He represented Lanark North as a Liberal in the Legislative Assembly of Ontario from 1867 to 1872 and the Canadian House of Commons from 1872 to 1879. He was born in Glasgow, Scotland in 1813 and came to Lanark County with his family in 1821. He served as reeve for Ramsay Township and also served as warden for Lanark County.
Galbraith was elected to the Ontario legislature in 1867 and reelected in 1871.
He resigned his seat in 1872 to run for a seat in the federal parliament. He was also director of the Brockville and Ottawa Railway.
He died while still in office in 1879.