As of 2003, he was also the chair of the Manitoba Federation of Labour's health and safety committee.
He also received an endorsement from the Manitoba Federation of Labour.
He worked as a commercial fisherman before entering political life, and was a Director of the Manitoba Federation of Fishermen for a time.
It later became the Manitoba Federation of Agriculture.
He was also a board member of the Manitoba Federation of Agriculture from 1954 to 1956.
Martin also served as business manager of the Manitoba Carpenters Union from 1989 to 1997, and was vice-president of the Manitoba Federation of Labour for a time.
Douglas joined the Manitoba Federation of Agriculture in 1956 as a youth director, and later became its executive secretary.
The Manitoba Federation of Labour is the Manitoba provincial trade union federation of the Canadian Labour Congress.
He joined the Independent Labour Party in 1925, and later became the first president of the Manitoba Federation of Labour.
In 2007, he was appointed to serve as ACTRA's representative on the Manitoba Federation of Labour's Human Rights Committee.