He worked for Marshall Field in Chicago during the 1870s before moving to Pembroke, Ontario, where he met his wife, Alice Dunlap.

While living in Mattawa, Cochrane hosted Prime Minister John A. Macdonald at his home while he recovered from a brief illness.

[4] Cochrane first ran for provincial office in 1902 as the Conservative Party candidate in Nipissing West in the 1902 election, but was defeated by Joseph Michaud.

Cochrane was then acclaimed into office in a by-election in Nipissing East, succeeding Charles Lamarche, who resigned to make the seat available to him.

After being re-elected in 1911 George Gordon, the Conservative MP for Nipissing, stepped aside to enable Cochrane to run in a by-election and he won the seat.