(From Wikipedia)

McCoy became a familiar voice on local radio stations, including WROX. A teenaged Ike Turner joined his band as a roadie in Clarksdale, Mississippi. Robert Lee McCoy disappeared in the mid-1940s.

Within a few years, he resurfaced in 1948 as the electric slide guitarist Robert Nighthawk and began recording for Aristocrat and Chess Records.The latter was also Muddy Waters' label. In 1949 and 1950, Nighthawk and Waters' styles were close enough that they competed for promotional activity. Waters was more marketable, as he was more reliable and a more confident stage performer, gaining him the attention.

In 1949, Nighthawk released the single "Annie Lee Blues"/"Black Angel Blues" on Aristocrat. The single was released under the name 'The Nighthawks', who were Nighthawk, pianist Ernest Lane, and bassist Willie Dixon."Annie Lee Blues" reached #13 on the Billboard R&B chart on December 31, 1949.Nighthawk recorded his final session for Chess (formerly Aristocrat) in 1950. He continued to perform and record, taking up with United Records and States Records 1951 and 1952, but did not achieve great commercial success.

In 1963, Nighthawk was rediscovered busking in Chicago. This led to further recording sessions and club dates and to his return to Arkansas, where he performed on the radio program King Biscuit Time, on KFFA. He also continued giving live performances on Chicago's Maxwell Street until 1964.