The petite, dark-eyed Lavin made her TV-movie debut in "The Morning After" (ABC, 1974), starring Dick Van Dyke, and went on to create the recurring character of Detective Janet Wentworth for the 1975-76 season of ABC's "Barney Miller" before finding her niche as strong, independent single mother and waitress Alice Hyatt on the long-running sitcom, "Alice" (CBS, 1976-85). Using the series as a springboard, she began directing episodes of "Alice" and formed her own production company (Big Deal Films, Inc.), ultimately producing and starring in a number of CBS movies (i.e., "The $5.20 an Hour Dream" 1980) that reinforced her image as a struggling, underappreciated, working woman. Following the demise of "Alice", Lavin made a triumphant return to Broadway and won a Tony award playing the mother in the third installment of Simon's autobiographical trilogy, "Broadway Bound" (1986). Nightly delivering a memorable monologue about once dancing with George Raft, she managed to create a heartbreaking, showstopping moment. In 1990 ,she--somewhat less successfully--replaced Tyne Daly as the archetypal stage mother, Mama Rose, in the Broadway revival of "Gypsy".
Lavin earned an Emmy nomination as executive producer of "Flour Babies" (1990), a "CBS Schoolbreak Special" which she also directed, and executive produced and starred as Edie Kurland, a mother who finds a second career as a TV commentator working alongside her daughter, in ABC's short-lived sitcom "Room for Two" (1992-93). Broadway beckoned in 1993, and she scored again, replacing Tony-winner Madeline Kahn as Gorgeous Teitelbaum in Wendy Wasserstein's "The Sisters Rosensweig", followed by an OBIE-winning performance in "Death Defying Acts" (1995-96), a series of three one-acts written by Woody Allen, David Mamet and Elaine May (she starred in the Allen and Mamet plays). Lavin was back on the Great White Way earning acclaim (and another Tony nomination) as Mrs. Van Daan in the revival of "The Diary of Anne Frank" (1997-98) but left the production earlier than she had originally planned in order to co-star as Florrie Bloom, the recently widowed mother of an advertising executive, in the NBC sitcom "Conrad Bloom" (1998). Although her feature films are few (most notable is her debut, "The Muppets Take Manhattan" 1984), she continues to frequently star in TV-movies like "Best Friends For Life" (CBS, 1998).