Armed with a husky voice, large blue eyes and a mop of frizzy hair that almost always gave a performance in itself, Ms. Brennan was an actress of little vanity. Though attractive, she frequently lent her characters an awkward discomfort—either comic or plaintive, depending on the role. In films like "The Sting," "Murder By Death," "The Cheap Detective" and "Clue" she was blowzy, ditzy, slatternly, woozy, careworn, vulnerable, caustic and jaded, but rarely uninteresting and always nothing less than human. Bogdonavich—who would go on to cast Ms. Brennan in his films "At Long Last Love," "Daisy Miller" and "Texasville"—first saw Ms. Brennan as the title character in the 1959 Off-Broadway musical Little Mary Sunshine, Rich Besoyan's spoof of the sort of florid operettas once written by Victor Herbert. The hit show proved a breakout role for the actress, though she later complained to the New York Times that it typecast her for a time as "that kooky girl from Mary Sunshine." She won an Obie Award and Theatre World Award for her performance.

She subsequently displayed her acting range by playing Annie Sullivan in a 1960 touring production of The Miracle Worker and Anna in a 1963 City Center staging of The King and I. On Broadway, she played Irene Molloy in the original Broadway production of Hello, Dolly!, and Merry May Glockenspiel in Besoyan's The Student Gypsy in 1963.

Off-Broadway, she acted alongside Susan Sarandon in John Ford Noonan's A Couple White Chicks Sitting Around Talking at the Astor Place Theatre. (Time magazine, reviewing the show, said she entered "with a musk of rampant libido.") A hit, it ran more than a year. She also appeared in the 1998 Off-Broadway premiere of Martin McDonagh's The Cripple of Inishmaan.

A frequent guest star on various television shows, she was nominated for Emmy Awards several times, including nods for "Taxi" (1981)," "Private Benjamin" (1981, '82, '83), "Newhart" ('89), "thirtysomething" ('91) and "Will & Grace" ('04).

She was born Verla Eileen Regina Brennan on Sept. 3, 1932, in Los Angeles. Her mother, Regina Manahan, had been a minor player in silent films. Eileen attended Georgetown University and the American Academy of Dramatic Arts. She got her start in television as a regular on "Rowan & Martin's Laugh-In," but left the show early on.

Her career was temporarily derailed in 1982 after she suffered near-fatal injuries when hit by a car while crossing the street. The accident forced her to leave her television series, "Private Benjamin." Her recovery lasted three years, and left her with an addiction to painkillers. She also battled alcoholism and breast cancer during her long career.

Her marriage to David John Lampson ended in divorce. She is survived by two children, Patrick and Sam.