He was elected to the House of Commons as MP for East Wicklow at the 1900 general election, until he resigned his seat on 10 June 1907, triggering the 1907 East Wicklow by-election.
Cogan became a member of Dublin Chamber of Commerce in 1907 and was elected its president in 1932.
A director of Hibernian Fire and General Insurance from its foundation in 1908, Cogan was chairman of the board for two decades until his death.
He died at his residence at Lyndhurst, Tivoli Terrace, Dún Laoghaire.
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