The union began as a coalition of autonomous local unions and militant workers' committees based in electrical manufacturing and radio assembly plants. When their request for a charter as a union for the unorganized electrical manufacturing industry was rejected by the American Federation of Labor, shop leaders chose to go it alone, launching their new national union in March 1936. UE became the first union chartered by the newly-established CIO.
UE grew rapidly, bringing better conditions and rights on the job to workers employed by industrial giants like General Electric, Westinghouse and RCA, as well as many other electrical manufacturing and machine companies. By the end of World War II, UE was the third largest CIO union, with a membership of 500,000.
Following the war, disagreements with the CIO leadership over the direction of the labor movement led to UE's withdrawal from the CIO in 1949; within months, a CIO convention "expelled" UE and 10 other unions with a total member of one million workers. The CIO joined big business, the press and politicians in smearing UE as "communist-dominated;" the CIO chartered a new union (IUE) to take the union's place.
UE came under ferocious attack as the anti-communist hysteria intensified in the early 1950s. Attempts were made to officially brand the union as a "subversive organization" and to deport UE leader James Matles. UE shop leaders were fired and blacklisted, even jailed. Politicians, big business and the CIO worked closely together to destabilize UE; the union lost more than half its members.
Steady organizing rebuilt the union in the 1960s and 1970s, but heavy losses followed in the 1980s depression due to mass layoffs and plant closings. Too often, profitable plants were closed by corporate giants eager for the super-profits to be gained through super-exploitation abroad. UE led the labor movement in resistance to plant closings and attempts by employers to wring concessions from unions by use of the plant-closing threat.
UE enjoyed real growth in the 1990s as a result of aggressive organizing. Independent unions affiliated with UE. The affiliation of the Ohio Turnpike workers' independent union in 1991 and the Iowa United Professionals in 1993 paved the way for a dramatic diversification of the union membership by economic sector and job.