Career
He represented Cornwall from 1879 to 1883, Cornwall and Stormont from 1886 to 1890 and Stormont from 1890 to 1894 in the Legislative Assembly of Ontario as a Liberal member. He grew up there and moved to Cornwall, Canada West in 1849, where he managed a gristmill. Mack went into business on his own, also helping to establish paper, cotton and woollen mills at Cornwall.
He served as reeve of Cornwall in 1871 and 1876 and as warden for the United Counties of Stormont, Dundas and Glengarry in 1878.
He was defeated by Alexander Peter Ross for the seat in the provincial assembly in 1883 but elected again in 1886.
