Jed (White Fang) also played the dog/alien in John Carpenter's The Thing (1982). His previous appearance was in The Journey of Natty Gann (1985). Gary Winkler's Alaskan Malamute "Teddy Bear" appeared on the film's poster when it premiered in theaters.
The title character was performed by Jed, an Alaskan Malamute-Canadian timber wolf hybrid, who also acted as "Wolf" in The Journey of Natty Gann (1985). Gary Winkler was his original owner. He later gave Jed to Clint Rowe to perform for cinematic productions.
The Bear that White Fang takes on to protect Jack is played by "Bart the Bear," who played the infamous "Bald Headed Bear" in The Great Outdoors (1988).
The caged dog Jack sees when his boat docks (and later seen fighting White Fang in town), is Buck from The Call of Wild, also by Jack London.
Basil Poledouris was hired to write the film's original score, having worked with director Randal Kleiser on The Blue Lagoon (1980). His score was rejected in mid-production in favor of one from Hans Zimmer. Unusually, both scores were fully recorded, one in London and the other in California, and pieces written by both Poledouris and Zimmer appear in the finished film.