Sykes was an editorial cartoonist for numerous papers, including Philadelphia's North American and Public Ledger. He was also the first (and only) editorial cartoonist for Philadelphia's Evening Public Ledger (1914-1942), the regular editorial cartoonist for LIFE magazine (1922-1928) and a regular contributor to Collier's and the New York Evening Post. His most well-known cartoon is probably Madonna and Child A.D. 1940, which depict the Virgin Mary and Jesus in gas masks.