1992 saw the actor take on a particularly iconic role, playing a sidekick in the "Saturday Night Live" spin-off feature "Wayne's World". As head-banging head case Terry, Tergesen gave a high-energy performance, and introduced the quickly-overused catchphrase "I love you, man!" into the pop culture lexicon. Tergesen reprised the role in the 1993 sequel, but didn't rest on the success of the film, instead doing Los Angeles theater and starring in a recurring capacity on several 1993 episodes of "Homicide: Life on the Street" (NBC). A Tom Fontana-created series, "Homicide" was a good starting ground for Tergesen, who found his feet playing a police officer who is blinded by a shot taken in the line of duty. The character's wife on the series was played by Edie Falco, another Fontana vet who would also work as a regular on "Oz".
A role as the sadistic and stupid older brother Chett on the USA Network/Sci-Fi Channel series "Weird Science" was an unfortunately little-seen opportunity for the actor to really stretch the bounds of malice and comedy, though nothing would come close to the depths of horror, fear, shame and love he would plumb as Tobias Beecher on "Oz", an alcoholic lawyer who goes to prison on a vehicular manslaughter charge and is, like most inmates, monumentally failed by the system. A series of violations and humiliations at the hands of Aryan leader Schillinger (J.K. Simmons) led to Beecher's downward spiral, while finding his own strength, forgiveness, and an unlikely love in Chris Keller (Christopher Meloni) started his slow uphill climb. Tergesen gave a courageous, unforgettable performance, breathing real life into Beecher and fleshing out the character's many dimensions and quirks.
"Oz" continued for season after season though it was surely too brutal to lure a solid mainstream audience. Tergesen kept busy with film roles in such independents as "The Shot" (1994), "George B" (1996) and "Diamonds" (1999) and a regular part in the very short-lived UPN police drama "The Beat". Another Fontana project, "The Beat" featured Tergesen as a firefighter with a police officer younger brother. The actor saw in the new millennium by adding to his resume with supporting turns in the cable-screened "Shot in the Heart" (lensed 2001 for HBO) and "Black Iris" (Showtime, 2001). The eclectic cast of the 2001 Sundance premiered improvisational parody "Perfume" included Tergesen alongside such varied performers as Paul Sorvino, Coolio and Sonia Braga.