[1] His artwork revealed the strong influence of artist Norman Lindsay, in addition to Franklin Booth, Joseph Clement Coll and J. Allen St. John.

His splash page contribution to Williamson's "Food for Thought" (Incredible Science Fiction 32, November–December 1955), a highly detailed alien landscape, is often regarded as a peak achievement in comic book illustration.

Krenkel only drew one solo story for EC, the unsigned "Time to Leave" (Incredible Science Fiction 31, September–October 1955), displaying a futuristic cityscape of architectural splendors.

When Lancer revived Robert E. Howard's creation Conan the Barbarian, with revisions by L. Sprague de Camp, Krenkel was cited by cover artist Frazetta as a consultant.

Krenkel drew one-page "Creepy's Loathsome Lore" and "Eerie's Monster Gallery" stories as well as rough layouts and inks for "H2O World" with collaborator Al Williamson.

He also contributed to several science fiction fanzines, including Richard A. Lupoff's Xero, the Burroughs-oriented ERBdom and Amra, devoted to the works of Howard.