The novice actor had to learn an Irish brogue practically overnight to play a young man whose combative relationship with his father and the recent death of his mother lead him to run off into the Irish countryside, where he meets and impregnates a young lass only to have the experience trigger a reconciliation with his father. Prior to that, he had played a soldier in "Renaissance Man", an NBC Page in "Quiz Show" and the son of Susan Sarandon and Sam Shepard in "Safe Passage" (all 1994). On the small screen, the strapping, strong-featured Keeslar made the most of his small role as the youthful collector, inspiring sensuous musing by Blanche DuBois (Jessica Lange) in "A Streetcar Named Desire" (CBS, 1995). Greater exposure greeted his title performance in "A Brother's Promise: The Dan Jansen Story" (CBS, 1996), which recounted how the Olympic speedskater's life was influenced by his sister's bout with leukemia.
Keeslar received praise for his turn as a mechanic coaxed into grease paint in "Waiting for Guffman" (1996), Christopher Guest's hilarious send-up of community theater. "The joke has always been that if I hadn't been signed by my agent," the actor told Newsday (November 29, 1998), "I would have become Johnny, working in a gas station in Michigan." He also made his NYC stage debut that year in Nicky Silver's "Fit to Be Tied", portraying the handsome Radio City Music Hall Christmas angel who almost too willingly becomes part of a dark triangle with a neurotic lonely man and his mother. Keeslar's decision to act in "The Stupids" and "Mr. Magoo" (both 1997) represented a temporary lapse in judgment, but he rebounded nicely with a comic romp spoofing ego-driven TV stars in "Sour Grapes" and a dramatic turn as the preppy stud in the district attorney's office who gets the girl in Whit Stillman's "The Last Days of Disco" (both 1998). He then returned to the stage as the Byronic tutor in the South Coast Repertory's production of Tom Stoppard's "Arcadia".
Keeslar was a standout in the acclaimed miniseries "Thanks of a Grateful Nation" (Showtime, 1998), portraying a gung-ho patriot reduced to a morose, disillusioned cynic with digestive and respiratory ailments following his tour of duty in the Gulf War. He was also the best thing about Gregg Araki's "Splendor" (1999), a punk homage to classic screwball comedies and menage a trois, for which he channeled his charisma as a tattooed, sexually insatiable rock drummer. Wanting to straddle both the film and theater worlds, the actor found time to work his wonders as a Jersey "cowboy" (and arguably the play's most complex character) in an Off-Broadway production of Laura Cahill's "Mercy" (1998) but has since stayed busy with screen work. He starred in the "Hallmark Hall of Fame" presentation "Durango" (CBS, 1999), a lush, location-look at an Irish cattle drive in the days before World War II, and then joined the ensemble casts of Wes Craven's "Scream 3" and Robert L King's "Psycho Beach Party" (both 2000), the latter adapted by the outrageous Charles Busch from his play.