Mac Lethal was born David McCleary Sheldon on July 25, 1981.
In 1998, he won several rap battles against local emcees from rival Kansas City high schools, and began to generate a buzz amongst the very small, tightly knit Kansas City underground hip-hop community. Mac entered the emcee battle at Scribble Jam hip-hop festival in August 2001 and took second place in the finals. He returned in 2002 and won the competition, and took second place in 2004. Sage Francis would later take Mac on the F*ck Clear Channel Tour in 2004.
In 2006, Sheldon founded Black Clover Records with longtime friend Jeremy Willis. Mac Lethal hosts Black Clover Radio Hour on the Kansas City alternative station 96.5 The Buzz. It has aired every Sunday night since 2006.