Florek moved from the stage to the small screen with a role in the 1985 detective TV-movie "Braker" (ABC), beginning a prolific television career. The following year, he portrayed a doctor in the fact-based telepic "Alex: The Life of A Child" and went on to 1987 featured guest spots on the series "Hunter" (NBC) and "Mr. President" (Fox). He appeared as a judge in 1988 the courtroom drama "The Trial of Bernhard Goetz", a production of "American Playhouse" (PBS) scripted directly from actual trial transcripts. Also that year he was acted in episodes of the crime series "21 Jump Street" (Fox), "Matlock" and "Beverly Hills Buntz" (both NBC) and additionally began a five season recurring role on the legal drama "L.A. Law". The actor gave a breakthrough performance on the popular NBC series playing David Meyer, a quirky businessman with an affection for legal secretary Roxanne (Susan Ruttan). Through the course of the series, Florek's memorable and remarkably irritating character wed, divorced and then remarried his beloved, and also teamed up with lawyer Becker (Corbin Bernsen) on a controversial divorce-themed instructional video. While appearing on "L.A. Law", Florek continued to make many guest appearances on television series, and included among his credits turns in "Major Dad", "Free Spirit" and a notable appearance as a hard-nosed principal who clashes with the titular mom on the ABC sitcom "Roseanne". From 1990 to 1995, Florek starred as the endearingly exasperated Captain Cragen on the NBC drama "Law & Order". Following this run, he was able to bide his time with additional guest shots on series including "Wings" (NBC), "Ellen" and "The Practice" (both ABC) and starring regular roles in the failed baseball sitcom "Hardball" (Fox, 1994) and the short-lived controversial comedy "The Secret Life of Desmond Pfeiffer" (UPN, 1998, as Abraham Lincoln) before bringing the cranky Cragen back into the homes of America in the NBC spin-off "Law & Order: Special Victims Unit" (NBC, 1999- ). Here Florek returned triumphantly to his acclaimed previous role, and his familiar take on the cynical captain was a welcome addition to the cast.
After making his film debut in the Alan Alda-directed comedy "Sweet Liberty" (1986), he followed up with a featured part the following year in Alan Parker's controversial thriller "Angel Heart". In 1988, Florek racked up credits in the "Five Corners", "Sunset" and "Moon Over Parador" and then took a high profile role in the Vietnam-era war drama "Flight of the Intruder" (1991). One of his more memorable big screen outings was as Fred's weasly boss Mr Slate in the feature take on the animated favorite "The Flintstones" (1994). Later that year he appeared in the panned "Getting Even With Dad", starring Macaulay Culkin and Ted Danson and had a supporting role in 1998's action thriller "Hard Rain"