James Marsters moved to Chicago, where his first professional acting role was Ferdinand in The Tempest at the Goodman Theatre in 1987. In this production, he was rolled onto the stage strapped naked to a wheel. He also appeared with well-known Chicago companies such as the Northlight and the Bailiwick and with his own group, the Genesis Theatre Company. Marsters was nominated for a Joseph Jefferson Award for his performance of the lead role of Robespierre in the six-hour drama Incorruptible: The Life, Death and Dreams of Maximilian de Robespierre in 1989.
In 1990, he moved to Seattle and, with Liane Davidson and Greg Musick, formed the New Mercury Theatre. In this and other companies, Marsters was involved in a wide range of plays, including Teechers (a British play by John Godber), Anouilh’s Antigone, an original work based on the Dr. Seuss books, and Shaw’s Misalliance.
In 1992, he got his first TV acting job on Northern Exposure, in which he appeared for two episodes as a bellboy and a church minister. He has made guest appearances on television series including Andromeda, as well as the independent films Chance (2002), Winding Roads (1999), and the USA Networkmovie Cool Money (2005). In 1999, he had a small role in the remake of House on Haunted Hill as a TV cameraman.
Marsters attracted the general public’s attention for his appearance as villain, and later anti-hero, Spike on season 2 of the television series Buffy the Vampire Slayer. For the role, Marsters spoke with a London accent, for which he received informal coaching from British co-star Anthony Head.
Spike had been intended as a short role, but the massive fan response prevented his character from being killed off, allowing Spike a presence throughout the second season. There were no plans to bring Spike back as a regular on Buffy, until the character Cordelia Chase was moved to the spin-off show, Angel.
After the conclusion of Buffy, Marsters carried Spike over to its spinoff, Angel, as a series regular in its fifth and final season. Marsters was asked to keep quiet about this, as his return was intended to be a surprise, but the network ruined it by promoting Spike’s return as soon as it could, in order to create media buzz and attract advertisers.
Aside from playing Spike, Marsters co-wrote a comic book one-shot for Dark Horse Comics, Buffy the Vampire Slayer: Spike and Dru. After Buffy the Vampire Slayer and Angel ended, Marsters became active with the canonical comic book series of both shows, particularly with stories centering around his character. A canonical graphic novel set during the seventh season of Buffy the Vampire Slayer, Spike: Into the Light, written by Marsters himself, was released by Dark Horse Comics on July 16, 2014.
Marsters has narrated the audiobooks for The Dresden Files, a series of detective novels with a supernatural bent and the side short story collection in the same universe, Side Jobs, were also recorded by Marsters. He did not originally record the Dresden book Ghost Story due to a scheduling conflict. This caused a fairly noteworthy public outcry by audiobook listeners. He returned for the following book Cold Days. On March 24, 2015, Jim Butcher announced that a new version of the Ghost Story audiobook was to be released on April 21, 2015, with Marsters returning as the narrator in response to fan demands.
In 2005, Marsters filmed a thriller, Shadow Puppets, with Jolene Blalock. Late that year, Marsters appeared on the television series Smallville playing Dr. Milton Fine—the popular Superman villain Brainiac—in eight episodes throughout the show’s fifth season. He reprised his role as Brainiac in a four-episode arc in the seventh season, and did a cameo voice-over in season eight. He returned for one episode in the show’s final season. On October 29, 2005, Marsters presented two performances of his own abridged adaptation of Shakespeare’s Macbeth with American actress Cheryl Puente as Lady Macbeth, followed by question and answer sessions with the audience and acoustic concerts in London.
In September 2006, Marsters’ interpretation of Godber’s Teechers was performed on the Queen Mary with two other actors in Los Angeles. This is a play he had received critical acclaim for as a stage actor prior to his television work. Marsters co-starred in the 2007 cinematic release of P.S. I Love You alongside Kathy Bates, Hilary Swank, and Gerard Butler. Released in September 2007, Marsters starred in the direct-to-DVD animated movie, Superman: Doomsday, providing the voice of iconic villain Lex Luthor.
In 2008, he guest-starred in Torchwood, a spin-off of the popular British science fiction television series Doctor Who, first appearing in the episode “Kiss Kiss, Bang Bang”, as the nefarious omnisexual time traveller Captain John Hart. He reprised the role in the last two episodes of the second season.
He portrayed “Piccolo Daimao” in the live-action film adaptation of the popular Dragon Ball manga and anime, directed by James Wong and produced by Stephen Chow, which was released worldwide on April 10, 2009.
On July 20, 2009, the film Moonshot aired on the History Channel in celebration of the 40th Anniversary of the 1969 moon landing. In this film, Marsters portrays Buzz Aldrin.
Also in August 2009, Marsters’ science fiction western, High Plains Invaders aired on the Syfy Channel. In this alien invasion flick, Marsters portrays Sam Danville.
On June 24, 2011, Marsters appeared in an L.A. Theatre Works radio production of The Importance of Being Earnest, in the part of Sir John Worthing, which aired on June 25, 2011.
He has appeared on Supernatural in the episode “Shut Up, Dr. Phil”, which aired October 21, 2011, alongside fellow Buffyverse co-star Charisma Carpenter. He also appeared in Warehouse 13 as Bennett Sutton, which aired in 2013.
Marsters had played in bands and solo in bars and clubs for many years and enjoyed several successful sell-out solo gigs at Los Angeles clubs before forming a band. For these solo gigs he mainly performed covers of classic folk and rock musicians such as Tom Waits, Neil Young, James Taylor, and Bruce Springsteen. He sang in “Once More, with Feeling”, a musical episode of Buffy: solo parts in “Walk Through the Fire” and “Something To Sing About”, and “Rest in Peace” completely on his own.
In 2003–04, Marsters was the lead singer for the rock band Ghost of the Robot. Their debut album Mad Brilliant was released on February 2, 2003. The band played its first gigs in Los Angeles and Paris. They went on to play successful dates in and around Los Angeles and two sold-out tours of Europe in 2003 and 2004. In addition to Mad Brilliant, they released three singles (“Valerie”, “David Letterman” and “New Man”) and one mid-length EP, It’s Nothing. All these releases carried tracks written and co-written by Marsters. Several of Ghost of the Robot’s earlier songs were loosely based on the Buffy the Vampire Slayer characters Buffy, Dawn, and Faith.
Marsters’ solo musical career was launched in October 2004, in London. His solo acoustic tour of the United Kingdom in April 2005 sold out. A new solo album “Civilized Man” produced by Chris Rhyne and Andrew Rosenthal was released on April 15, 2005. It includes several new songs as well as the popular “Katie” and “Smile”. He has played songs from the album live in Detroit, Houston, and Sacramento. Ten of the eleven songs are written by Marsters.
His album Like A Waterfall was produced by Ryan Shore and features several other musicians including Blair Sinta, who has drummed for Alanis Morissette, and Five for Fighting bass player Curt Schneider.
In 2010 James’ music career continued when the band Ghost of the Robot reformed: they have since released the album B-Sider which is available on iTunes. Afterwards, in 2011, the album Murphy’s Law was released which is also available for download in iTunes. There are also multiple other EPs available on the iTunes Store.