He made a series of recordings for Bluebird Records from 1939 through 1942 and regularly played with his friend Robert Petway. He can be heard shouting in the background on Petway's 1942 recording "Boogie Woogie Woman".
McClennan made an immediate impact in 1940 with his recordings of "Shake 'Em On Down", "Bottle It Up and Go", "Whiskey Head Woman" and "New Highway No.51".
He left a powerful legacy that included "Bottle It Up and Go," "Cross Cut Saw Blues" (covered by Albert King), "Deep Blue Sea Blues" (aka "Catfish Blues"), and others whose lasting power has been evidenced through the repertoires and re-recordings of other artists."He had a different style of playing a guitar" Big Bill Broonzy remarked drily. "You just make the chords and change when you feel like changing"[
Although nothing is known of what happened to Petway, McClennan was occasionally seen in Chicago with Elmore James and Little Walter, two other artists who came from the Delta. McClennan is reported to have died from alcoholism in poverty in Chicago, Illinois, in 1962.