Prosser was part of Dark Horse Comics from its early days, and was one of five creators, who as Team CGW created the Comics' Greatest World line for Dark Horse Comics. Since then, he has written for many Dark Horse titles, and moved into editorial duties, most notably on Frank Miller's Sin City: A Dame to Kill For, and various licenced Aliens and Predator comics.

He also pencilled part of Godzilla #5, one of Dark Horse's earliest licenced properties, in December 1988.

In addition to his work with Dark Horse, Prosser wrote the final ten issues (#80-89) of the Grant Morrison-launched DC/Vertigo series Animal Man in 1995, and has written comics set in the world of the Gathering for Armada/Acclaim Comics.

Writer

• The Mark #4-6 (Sep 1988-Jan 1989)
• Spacehawk #1 (Nov 1989)
• Mayhem #1-4 (Dark Horse, May-Sep 1989)
• Exquisite Corpse #1 (Dark Horse, Jan 1990)
• True North II (1991) Benefit comic for the Canadian Comic Legends Legal Defense Fund
• "Fifth Anniversary Special" in Dark Horse Presents: Fifth Anniversary Special (Apr 1991)
• Aliens: Hive #1-4 (Dark Horse, Feb-May 1992)
• "From the Cradle to the Grave" in Primal (1992)
• "Night of the Living Deadline" in Deadline #1 (Apr 1992)
• "Hunka Hunka Burnin' Deadline" in Deadline #2 (May 1992)
• "Off Deadline" in Deadline #3 (Jun 1992)
• "Prescription Strength Deadline" in Deadline #4 (Jul 1992)
• Aliens #1 (with Mark Verheiden (Jul 1992)
• Andrew Vachss' Hard Looks #3, 8-9 (Jul 1992, May-Jul 1993)
• "Workingman's Deadline" in Deadline #5 (Aug 1992)
• Dark Horse Comics #8-10 (Mar-May 1993)
• Special Limited Edition Arcadia Collection #1 (1993)
• Comics' Greatest World Arcadia #1-4 (Dark Horse, Jun 1993)
• The Adventures of a Tattooed Man #1-4 (with art by Warren Pleece, Vertigo, Jul-Oct 1993)
• By Bizarre Hands (adapter) #2-3 (May—June 1994)
• Will to Power #1-3 (Dark Horse, Jun 1994)
• Predator: Invaders from the Fourth Dimension (Dark Horse, Jul/Aug 1994)
• X: One Shot to the Head #1 (Dark Horse, Aug 1994)
• Vertigo Rave (DC/Vertigo, Nov 1994)
• "Ghost Stories" in Ghost TPB (Apr 1995)
• Bram Stoker's Burial of the Rats #1 (Roger Corman's Cosmic Comics, Apr 1995)
• Animal Man #80-89 (DC/Vertigo, Feb-Nov 1995)
• The Comics Magazine #49 (Wizard, Sep 1995)
• The Gathering: Antiquities War #1-4 (Armada, Nov 1995-Feb 1996)
• Eternal Warrior Fist and Steel #1-2 (Valiant, May-Jun 1996)
• Predator: Jungle Tales #1 (May 1996)
• the Gathering: Dakkon Blackblade (Armada, Jun 1996)
• The Gathering #1-2 (Armada, Sep-Oct 1996)
• Crow: Wild Justice #1-3 (Kitchen Sink Press/Top Dollar Comics, Oct-Dec 1996)
• Gen13 #36 (Image, Dec 1998)
• J. O'Barr's The Crow: A Cycle of Shattered Lives #0 (Kitchen Sink Press, Dec 1998)
• Harvest TPB (1998)

Editor

• Deadline USA #1-2 (Sep-Nov 1991)
• Cyberantics HC (1992)
• Andrew Vachss' Hard Looks #1-10 (Mar 1992-Sep 1993)
• Deadline #1-5 (Apr-Aug, 1992)
• Freaks' Amour #1 (Jul 1992)
• James Bond: Serpent's Tooth #1-3 (Jul 1992-Feb 1993)
• Dark Horse Comics #1-11 (Aug 1992-Jul 1993)
• Primal #1-2 (Oct-Dec 1992)
• Ring of Roses #1-3 (Nov 1992-Jan 1993)
• Thirteen O'Clock #1 (Dec 1992)
• Dark Horse Presents #69 (Feb 1993)
• Race War #0-4 (Feb-Oct 1993)
• James Bond: A Silent Armageddon #1-2 (Mar-May 1993
• Comics' Greatest World: Vortex #1-4 (Sep 1993)
• Dead in the West #1-2 (Oct 1993 - Mar 1994)
• Sin City: A Dame to Kill For #1-6 by Frank Miller (Nov 1993-May 1994)
• Andrew Vachss' Underground #1-4 (Dark Horse, Nov 1993-May 1994)
• Music of the Spears #1-4 (Jan-Apr 1994)
• Martha Washington Goes To War #1-2 by Frank Miller & Dave Gibbons (May-Jun 1994)
• White Like She #1-2 (May-Jun 1994)