The league’s players association made the official announcement Tuesday afternoon.
Tretter, who has an industrial labor relations degree from Cornell, replaces outgoing president Eric Winston. Winston served three two-year terms.
The Browns signed Tretter in 2017 as a free agent after he spent his first four seasons with the Green Bay Packers. He signed a three-year $32.5 million extension that included $23 million in guaranteed money last November.
Members of the NFLPA are currently voting on a new collective bargaining agreement through Saturday at 11:59 p.m. ET. The current deal expires following the 2021 season.