Daughter of John Gerald Brennan and Regina "Jeanne" Menehan.
In 1982, she was seriously injured in a car crash by a drunk driver.
Has two sons: actor Patrick Brennan (born on Christmas Day, 1972), a former college basketball player; and singer Sam Lampson.
While studying at the Academy of Dramatic Arts in New York, Eileen shared an apartment with The Golden Girls (1985) star, Rue McClanahan.
Recovering member of Alcoholics Anonymous since 1976.
While playing Miss Hannigan in a production of Annie in 1989, she broke her leg after falling from the stage into the orchestra pit.
Mother-in-law of Jessica Moresco.
Has appeared with Cybill Shepherd in four films: The Last Picture Show (1971), Daisy Miller (1974), At Long Last Love (1975) and Texasville (1990).
Best known for her role as the spiteful Captain Doreen Lewis in the comedy film Private Benjamin (1980) and the situation comedy Private Benjamin (1981).
Prior to Hello, Dolly!, she created the title role in the long-running Off-Broadway musical Little Mary Sunshine, which opened in 1959.
She was cremated upon her death.
Two featured characters in Norman Lear's "All That Glitters" television series were Eileen Brennan as Ma Packer and her lazy son, Sonny Packer, played by Tim Thomerson. Sonny's (Thomerson's) role idol and wannabe impersonation of an Elvis Presley character, always strumming his guitar, practicing swinging hips and rock movements was diligently encouraged by his Ma (Eileen Brennan) Packer. Their principal abode was a run down farm shack. In preparation for the first introduction of the outlandish pair, director Herb Kenwith and Eileen requested the littered straw and dirt studio set floor be inhabited with a small pot bellied pig and a dozen chickens. The first day to video-tape Ma and Sonny Packer's introduction in the series, Eileen picked up one of the hens, holding the chicken in her arms like a pet cat, petting and soothing the clucking hen while performing her character's motherly role. The entire week of staged scenes, Eileen carried the same hen in her arms, with the chickens pecking seeds from the straw on the ramshackle shack floor. The following week, the "All That Glitters" staff of women producers decided to cancel Eileen's on-set chicken wrangler and his livestock. Arriving early on the ramshackle set for rehearsal, Eileen and Herb confronted the dull witted lady producers. Where were the Chickens? Canceled to save money on a chicken wrangler and his flock of hens! The cast and crew waited for one hour while the wrangler and his flock of hens could arrive. Thereafter, Eileen, her chicken-hen co-star, with the floor flock of hens were featured until Ma moved uptown, with Sonny becoming a full fledged rock star on a local television station talent show, landing a gig at a local Western bar and stardom! Ma Packer, now a sexy glamorous theatrical agent, became a music-rock group phenomena.
Acting mentor and friend of Lorna Patterson.
She made her Hollywood film debut in the comedy Divorce American Style (1967) starring Dick Van Dyke, Debbie Reynolds and Jason Robards.
It was in her role as the growling Captain Doreen Lewis in the film "Private Benjamin," who oversaw the unlikely Army enlistee played by Goldie Hawn, that Brennan found her biggest success. The actress was the epitome of the "gruff but lovable" type, often bringing comedic sparkle to workaday frustrations while playing figures worn weary by their lives but still able to laugh off the worst. The film was a box-office hit and earned three Oscar nominations, including one for Brennan as best supporting actress. She won an EMMY for her part in the television spin-off. Brennan was nominated seven times for EMMY Awards, including for appearances on "Taxi," "Thirtysomething," "Newhart" and "Will & Grace".
In 1973 Eileen Brennan had supporting acting parts in "The Sting" with Robert Redford and Paul Newman and "Scarecrow" with Al Pacino and Gene Hackman. Brennan often excelled in roles as a wisecracking hard-bitten sidekick, such as the madam in "The Sting" and her turns in the Neil Simon scripted 1976 "Murder By Death" and 1978 "The Cheap Detective." As Eileen Brennan was launching the 1979 television comedy "13 Queens Boulevard," Brennan noted how often she was cast as comedic characters on the fringe when she said, "I've just about exhausted the market for madams. I love to pay them and I hope I have given each of the ladies a certain amount of individuality. But it's always a challenge to develop new types".
She originated the role of Irene Malloy in the original Broadway production of Hello, Dolly! in 1964.
She was a lifelong Democrat.