Nicholas Holmes

as Noah

as Ernest (voice) (52 episodes)

as Professor Dixon

as Hudson Harper (voice)

as Hudson Harper (voice) (1 episode)

as Young Lassie

as Josh (1 episode)

as Young Frank (12 episodes)

as Young Johnny (3 episodes)

as Hudson Harper (voice) (13 episodes)

as Ryan

as Bill (voice) (156 episodes)

as Andy Landry (1 episode)

as Joel Hynek (12 episodes)

as Young Max

as Frederick (1 episode)

as Dooley

as 1950s Young Mack's Dad

as Kid #2

as Young Norman (1 episode)

as Young Boy (1 episode)

as Jake (voice) (3 episodes)