He began working at the Bond Bread Company before World War II, where he organized a local of the Bakery and Confectionery Workers International Union of America.
He became a full-time organizer for the union in 1941, but left the role to serve in the US Army as a paratrooper during World War II.
As executive vice president, DeConcini was prominent in efforts to bring the two unions back together, which occurred in 1969.
[1] Membership of the union fell under DeConcini's leadership, but he set up its first political action committee.
He served on the executive committee of the AFL-CIO, and also as a trustee of the George Meany Center for Labor Studies.