In 1944, he married Mary Wilson, then an ensign in the United States Navy Nurse Corps.
[3] In 1956, McCormack was the Democratic nominee for sheriff of Norfolk County, but lost to incumbent Samuel H. Wragg by 33,000 votes.
In 1958 he upset incumbent state senator Philip G. Bowker to represent the Norfolk and Suffolk District.
[3] McCormack chose to wait until the end of the 1959 legislative session to assume office.
He later served as Norfolk County's liaison officer to the state Department of Corrections until his retirement in 1977.