Born in the Bronx, Klein moved to California as a young man and became wealthy running car dealerships, and later moved into insurance and finance. A lifelong interest in sport saw him repeatedly invest his money in various sporting endeavours: his ill-fated attempt to gain a franchise for a Los Angeles Major League Baseball team in 1960, his purchase and racing of more than a hundred racehorses, many of them champions.
In 1966, he and business partner Sam Schulman obtained the franchise for what would become the Seattle SuperSonics in the NBA, and the San Diego Chargers in the NFL. He would go on to manager of both these teams at various times, although his record at both is mixed.
Klein died in 1990. He was 69 years old.
