Mort Walker
Mort Walker is credited as writer on 72 issues, penciller on 72 issues, inker on 68 issues, cover artist on 45 issues and others in grailworth's catalog, 46 issues of them across 11 series we value. Characters first seen in issues they wrote or drew include General Halftrack and Pete the Tramp.
Characters they introduced
Every issue
Beetle Bailey (1956) 1 issue
Beetle Bailey (1962) 4 issues
Beetle Bailey (1978) 3 issues
Beetle Bailey (1992) 4 issues
Four Color (1942) 4 issues
Mad (1952) 2 issues
Popeye (1966) 1 issue
Credits from the Grand Comics Database, CC BY-SA 4.0.