Frank Sinatra began his career in the late 1930's and early 1940's, as a vocalist with which two famous orchestras?

Before he was the legendary "Chairman of the Board," a young Frank Sinatra was a "boy singer" for the biggest names of the Big Band era. His professional journey began in 1939 when trumpeter and bandleader Harry James hired him after hearing him on a local radio broadcast. Sinatra signed a one-year contract and recorded several songs, including "All or Nothing at All," which would ironically become a major hit only after he had achieved solo stardom years later.

While the job with James was a crucial first step, it was Sinatra's move in 1940 to the more established Tommy Dorsey Orchestra that catapulted him to fame. With Dorsey, he scored his first number-one hit, "I'll Never Smile Again." It was also during this period that Sinatra famously studied Dorsey's trombone playing to develop his own seamless long-phrasing vocal technique and incredible breath control. This apprenticeship with two of the era's most prominent orchestras provided the foundation (Review) for his solo career, turning him from a band vocalist into a national phenomenon.