A compact, serious actor, Plummer's work often falls into the category of "Black hoodlums", but he always brings a sensitivity to those roles. Plummer has worn dreadlocks for most of his roles regardless of the characters' so-called class distinctions. After receiving training at the East Bay Center for the Performing Arts and the Contra Costa Performing Arts Center, he began his career in TV. In 1987, Plummer made his debut as an unsavory character in the NBC miniseries "Hands of a Stranger" and followed as a street tough in the biopic "The Father Clemens Story" (NBC, 1987) starring Louis Gossett Jr. Subsequently, he appeared as a gang leader in "The Women of Brewster Place" (ABC, 1989), as a man who had recently moved to the neighborhood just prior to the Watts riots in "Heat Wave" (TNT, 1990) and as a gang leader in Steve Anderson's short film "Hearts of Stone" (Showtime, 1991). Plummer made occasional guest appearances on series including "Beauty and the Beast" (CBS, 1987), "Tour of Duty" (CBS, 1988) and the premiere of "Cop Rock" (ABC, 1990). During the first season of "ER" (NBC, 1994-95), he played a recurring role as a member of the emergency room's support staff.
Plummer's work in features has ranged from supporting roles to leads. His early work included playing a kid from Harlem in "Who's That Girl?" (1987), the young thug High Top in Dennis Hopper's "Colors" (1988) and a busboy with dreams in Garry Marshall's "Frankie & Johnnie" (1991). He got his biggest break in Steve Anderson's "South Central" (1992), as Bobby Johnson, the ex-con father who does not want his son following his example. Plummer also acted as a creative consultant on the film. But few feature leads followed. He appeared in the Hughes Brothers' "Menace II Society" (1993) and as the motorist whose fancy sports car is borrowed by Keanu Reeves in "Speed" (1994). Plummer went on to portray James Smith, the choreographer more interested in bedding women in "Showgirls" and a political activist-cum-rapper in "Strange Days" (both 1995). He appears as a TV cameraman with Michelle Pfeiffer and Robert Redford in "Up Close and Personal", and in support of Robert Pastorelli in "The Asphalt Quartet", of Tom Berenger, Ernie Hudson and Diane Venora in "The Substitute", and of Jeff Fahey in "Waiting for the Moon" (all 1996).