Frank Welker Scooby-Doo / Fred Jones (voice) Grey DeLisle Daphne Blake / Wonder Woman (voice) Matthew Lillard Shaggy Rogers (voice) Kate Micucci Velma Dinkley (voice) P.J. Byrne J.B. (voice) Victoria Grace Mercy (voice) Charles Halford Lex Luthor (voice) Nolan North Computer / Joker / Superman (voice) Tara Strong Helen / Lois Lane / Harley Quinn (voice) Fred Tatasciore Solomon Grundy / Perry White (voice) James Arnold Taylor Jimmy Olsen / Rex Ruthor (voice) Niccole Thurman Mayor Flemming (voice)