During his twelve years as IAM President, he substantially expanded the union's human rights, community services, job safety, public relations and organizing programs.
Discharged from the Naval Reserve on July 15, 1947, Winpisinger returned to Cleveland where he worked as a "gypsy mechanic", repairing automobile transmissions at local service stations.
He secured a job as a mechanic at Lake Buick, a dealership on Lavern Avenue on Cleveland's West Side, and on July 15, 1947, obligated to Local Lodge 1363 of the International Association of Machinists and Aerospace Workers.
Union officials quickly recognized Winpisinger's talent and appointed him to the National Field Staff, as a Special Representative, in 1951, and assigned him to organizing tasks in Ohio, Michigan and Pennsylvania.
IAM President Al Hayes promoted him to a position in Washington, D.C. in 1955 to work on a joint organizing program with the International Brotherhood of Teamsters.
Winpisinger was then assigned to a variety of jobs throughout the union, including servicing members in the automotive, airline and brewery industries.
He negotiated the union's first collective bargaining agreement with Continental Airlines in 1961, and was appointed Automotive Coordinator in 1965, overseeing the contracts of more than 100,000 auto mechanics.
That, in turn, Winpisinger pointed out, had a negative impact on the American economy, causing production interruptions and layoffs, denying his members their right to work.
In 1979, he was the subject of a Columbia Broadcasting System (CBS) 60 Minutes television feature proclaiming, "Wimpy, a New Breed of Labor Leader."
Winpisinger showed his readiness to push the boundaries of what many considered appropriate behavior for trade union leaders in one other important area.