 He was an active Freemason from his stay in Adelaide until his death.He played a key role in the formation of the Grand Lodge of Victoria in 1883, of which he became Grand Master.The Coppin Masonic Lodge in East Brunswick bears his name as does Coppin Hall at the Royal Freemasons Homes

In April 1858 Coppin began to take an interest in public affairs — he became a councillor in the Richmond municipality, and in October 1858 was elected for the South Western Province in the Victorian Legislative Council for a term of five years.