Ballard made her performing debut in her native Cleveland at age 12 and three years later was singing at the local Stage Door Canteen. In 1943, Ballard was performing at The Bowery, a Detroit club, when she was "discovered" by bandleader Spike Jones, who took her on tour with his group until 1945. Ballard settled in New York and appeared in the revue "Three to Make Ready" (1946). She went to London in 1950 to perform in the revue "Touch and Go", but it was not until 1954 that she really solidified her status as a stage performer. That came with the musical "The Golden Apple", in which she was a zany Helen of Troy who introduced the song "Lazy Afternoon". More Broadway appearances and better clubs for her cabaret act followed. Eventually, Ballard was featured as the Incomparable Rosalie in "Carnival" (1961), adapted from the film "Lili". In the early 70s, she starred as producer-radio/TV star Molly Goldberg in the short-lived musical "Molly" (1973) and played Lola in "Sheba" (1974), the musical version of William Inge's "Come Back, Little Sheba". She later succeeded Estelle Parsons as Ruth in the New York Shakespeare Festival production of "The Pirates of Penzance" (1981).
Hollywood beckoned in 1958 and Ballard made her film debut in "The Girl Most Likely", a weak Jane Powell vehicle at the very end of the reign of the movie musical. Ballard was the heroine's friend, a second lead, a comic addition. With the decline of the musical genre, it became clear that film work would not be her bread and butter. Still, Ballard was in the Polly Adler biographical film "A House Is Not a Home" (1964), teaching star Shelley Winters a thing or two. She was Jack Weston's overbearing wife in "The Ritz" (1976) and Jodie Foster's coach in "Freaky Friday" (1977).
TV work has been more fulfilling, providing Ballard with the chance not just to act, but to sing as well. She broke into the medium on an installment of "The Mel Torme Show" in 1951 and was a regular on "Henry Morgan's Great Talent Hunt" (NBC, 1951), "The Perry Como Show" (NBC, 1961-63) and "The Steve Allen Comedy Hour" (NBC, 1980-81) as a singer/comedienne. As a comic actress, she spent a season as Doris Day's restaurateur/neighbor on "The Doris Day Show" (CBS, 1970-71) and was an off-beat psychic in the syndicated "What a Dummy!" (1990-91). The latter was created by Leslie Eberhard who had written cabaret material for Ballard for many years. Occasionally, Ballard has played in TV dramas, although often as the pepper-up-the-scene character. She was Vincent Gardenia's wife watching him turn into a movie mogul in "The Dream Merchant" (syndicated, 1980) and the owner of an Italian restaurant in the two-hour TV-movie/pilot of "Due South" (CBS, 1994).
Throughout it all, Ballard has continued to perform in cabarets and clubs, headlining some of the most prestigious rooms in the country, including two years (1975-76) at the Persian Room at Manhattan's Plaza Hotel, Mister Kelly's in Chicago, and others. She has also performed her one-person show, "Hey Ma...Kaye Ballard" off-Broadway and in various venues around the country and has been a frequent guest on talk shows with more than 150 appearances on "The Tonight Show" alone.