Cameron Monaghan

as Harry Bosch(8 eps)

as Caius

as Cal Kestis (voice)(2 eps)

as Clyde

as Sergei (voice)

as Special Agent Finley Sterling

as Chris Decker

as Kamandi (voice)

as Ian Gallagher(1 ep)

as Jeremiah Valeska/The Joker (archive footage)

as Self

as Connor Kent / Superboy (voice)

as Self(1 ep)

as Connor Kent / Superboy (voice)

as Luke Hunter

as Ross

as Aaron(1 ep)

as James Walker

as Tom Fairfax(12 eps)

as Jerome Valeska(12 eps)

as Jeremiah Valeska(10 eps)

as Joker(1 ep)

as Asher

as Adam McCormick

as Jeff

as Mason Ashford

as Jake

as Corey Doyle

as Corey(6 eps)

as Ian Gallagher(134 eps)

as Jack

as Cody Grice(1 ep)

as Jonathan McKenna(1 ep)

as Larry Parker

as Bob Andrews

as Young Boy 1(1 ep)

as Dexter

as Elliot(1 ep)

as Tyler Carson(1 ep)

as Bob Andrews

as Traffic Cop #1

as Kevin O'Doyle

as (archive footage)(1 ep)

as Jeffrey Charles(1 ep)

as Twin 1 (voice)(1 ep)

as Todd(1 ep)

as Timmy

as Palmer Noid(3 eps)

as Nick Peyton(1 ep)

as Winthrop Paroo

as Danny Cooper(1 ep)

as Alex

as student (uncredited)

as Chad(6 eps)

as Eddie Sandow(1 ep)

as Eddie Sandow(1 ep)