The family moved to Astoria, Queens, when Thomas was still a child.
[1] In 1938, he married Helen M. Fisher (born 1908), and they had three children.
On February 7, 1956, he ran in a special election for the State Senate seat vacated by the resignation of Frank D. O'Connor, but was defeated by Republican Bernard Tompkins.
In November 1956, Duffy defeated Tompkins who ran for re-election.
He died on April 11, 1979, in Calvary Hospital in the Bronx.