He left Monroe and worked briefly with the Osborne Brothers until he formed his own band, The Sunny Mountain Boys, in 1955. The classic lineup of this band, with J. D. Crowe and "Big" Paul Williams (stage name for Paul Humphrey), defined his "Good 'n Country" style, a commercially oriented, crowd-pleasing bluegrass with simple harmonies, catchy melodies, and a strong rhythm propelled by Martin's effective guitar playing. He credited himself with inventing the "G" run, a guitar lick used widely in the bluegrass genre. However, aural evidence from the period before Martin began performing professionally clearly shows Lester Flatt using this run when backing Bill Monroe.