Frank Edward "Fitz" Fitzsimmons was a secondary antagonist in the 1992 film Hoffa.
Fitz, as Hoffa eventually came to call him, was a young dock worker who came to know the Teamsters union organizer Jimmy Hoffa in the early 1930s when Hoffa tried to organize the dock where he and Bobby Ciaro worked.
Over the years Fitz became one of Hoffa's most important union allies as Hoffa rose steadily in power and influence, eventually becoming President of the International Brotherhood of Teamsters. At Hoffa's orders Fitz purged the head office of those not loyal to him and brought in a staff apparently loyal to Hoffa.
When Hoffa and Bobby went to prison after being convicted of fairly serious crimes, Hoffa designated Fitz as President of the Teamsters while Hoffa was in prison. Being far more interested in playing golf Fitz was discovered to be far easier to control than Hoffa. Fitz stopped working as hard to get Hoffa out of prison once he settled into the Presidency. Using allies in the Nixon White House the mafia engineered a release for Hoffa, but it came with a price - Hoffa was barred from union activities for ten years.
Hoffa was not pleased that Fitz had taken the Presidency from him and began working to get the ban on his being part of the Teamsters overturned. However by then the mob had tired of Hoffa and when Hoffa threatened to go public with damaging information the mob had Hoffa assassinated at a diner outside of Detroit, leaving Fitzsimmons in charge of the Teamsters.