Webb was born in Baltimore, Maryland, to William H. and Marie Webb. The year of his birth is disputed. The Encyclopædia Britannica and Allmusic indicate 1905, and this seems to be supported by censusinformation. Other publications claim other years. During Webb’s lifetime, a December 1937 DownBeatmagazine article, “The Rise of a Crippled Genius”, stated he was born in 1909, which is the year that appears on his grave marker. In 1939, The New York Times stated that Webb was born in 1907, the year also suggested in Rhythm on Record by Hilton Schleman.
Webb was one of four children; the other three were sisters (Bessie, Mabel, and Ethel). His sister Mabel married Wilbur Porter around 1928. When an infant, Webb fell down some stairsteps in his family’s home, crushing several vertebrae and requiring surgery, from which he never regained full mobility. The injury progressed to tuberculosis of the spine, leaving him with short stature and a badly deformed spine which caused him to appear hunchbacked. The idea of playing an instrument was suggested by his doctor to “loosen up” his bones. He supported himself as a newspaper boy to save enough money to buy drums, and first played professionally at age 11.