Lang was born with the name Salvatore Massaro, the son of an Italian-American instrument maker in Philadelphia, Pennsylvania. At first he studied to learn violin. In school he became friends with Joe Venuti, who he would work with for much of his carrer. He was playing professionally by about 1918, playing violin, banjo, and guitar. He worked with various bands in the USA's north-east, worked in London in 1924, then settled in New York City. He played with the bands of Venuti, Adrian Rollini, and Roger Wolfe Kahn in addition to doing a large amount of freelance radio and recording work. In 1929 he joined Paul Whiteman's Orchestra, and can be seen and heard in the film The King of Jazz. When Bing Crosby left Whiteman, Lang went with Bing as his accompanyist.
Eddie Lang died from infections following a tonsillectomy in New York City.