In 1954, he emigrated to Halifax, Nova Scotia and then moved to New Brunswick where he settled in Fredericton, established a window cleaning business,[2] and joined the province's Co-operative Commonwealth Federation which became the New Democratic Party in 1962.
In 1970, he was approached by a group of young radical socialists active at the University of New Brunswick and established a riding association in York—Sunbury with himself as president.
The Waffle became a dominant force in the New Brunswick NDP in 1971 and Callaghan announced his intention to seek the party's leadership.
Due to conflicts between Wafflers and anti-Wafflers over the legitimacy of the party's fall convention at which the New Brunswick Waffle manifesto had been approved, the party split into two, on October 16, 1971, with one faction led by Callaghan and a second, non-Waffle faction led by J. Albert Richardson with both men claiming to be NDP leader.
Callaghan and many other Wafflers did not attend the special convention which saw the re-election of J. Albert Richardson as party leader.