After writing for MADtv and starring in his own 1996 comedy special for HBO , he went on to garner notable roles in films and television shows .
Oswalt began performing stand - up comedy on July 18 , 1988 .
After writing for MADtv and starring in Oswalt 's own 1996 comedy special for HBO , Oswalt went on to garner notable roles in films and television shows .
Oswalt began performing stand - up comedy on July 18 , 1988 .