Quinn was born and educated in Dublin. Her father was a violinist and the family was musically inclined. She began her career in Dublin singing with local bands, the most prominent of which was the Johnny Devlin Orchestra in the Crystal Ballroom, although her singing had been recorded as early as 1942, when she was a teenager. She also sang at Dublin's Theatre Royal with the house orchestra and Jimmy Campbell. She was noted for one of her first songs, "The Isle of Innisfree".
After coming to the United States in 1954, she appeared on the Arthur Godfrey's Talent Scouts radio program in 1955 and won the contest. Her voice and performing style was compared to that of Judy Garland and other popular singers. She became a regular on the show, appearing daily, singing and telling funny anecdotes about her life. She went on to appear on the television version of Arthur Godfrey and His Friends. Unlike many of the so-called "Little Godfreys", whom Godfrey capriciously dismissed from his shows and left with bitter feelings, Quinn remained a frequent guest throughout Godfrey's television career and appeared on the CBS radio version of Arthur Godfrey Time which he hosted until 1972. She continued to be a favourite with audiences and made guest appearances on The Pat Boone Chevy Showroom (three times between 1957 and 1960) The Ed Sullivan Show, The Joe Franklin Show, Match Game, Candid Camera, and other variety and talk shows. 
Since then she went on to appear in numerous musical road shows and has starred in Wildcat, Finian's Rainbow and The Sound of Music. She performed for presidents John F. Kennedy and Lyndon B. Johnson. Her annual Saint Patrick's Day Concerts at Carnegie Hall sold out for more than two decades. She appeared in numerous television commercials and has recorded many successful albums. She received a Grammy Award nomination for her children's recording of "Patrick Muldoon and his Magic Balloon". One of her biggest hits was "The Whistling Gypsy Rover".
She continued to record and many of her early recordings have been reissued on CD. In 1991 she was the second woman to receive the John F. Kennedy Award for excellence in her field of activity. She continues to perform her cabaret show throughout the United States as well as maintaining a commitment to numerous American and Irish charities. Quinn has been a longtime resident of Leonia, New Jersey, acquiring her first home there after coming to the United States.
Quinn was married to Irish businessman and impresario William "Bill" Fuller (1917–2008); the marriage eventually ended in divorce. Quinn never remarried but Fuller did. The couple had four children, Michael, Jane, Terry and Sean. Michael predeceased his parents, dying suddenly from an undiagnosed cardiac ailment at age 31 in 1988.
- Patrick Muldoon and His Magic Balloon (1965), amazon.com; accessed 11 December 2014.
- Carmel Quinn's Ireland, regorecords.com; accessed 11 December 2014.
- Date of birth given as 31 July at Quinn's official website, carmelquinn.net; accessed 30 June 2016.
- Profile (as Carmel Q. Fuller), Intelius.com; accessed 30 June 2016.(subscription required)
- Emblen, Frank, "New Jersey Guide", The New York Times, 23 February 1986; accessed 14 August 2007.
- Profile, imdb.com; accessed 11 December 2014.
- Official Carmel Quinn website, carmelquinn.net; accessed 11 December 2014.
- Roura, Phil. "Carmel Quinn Hits The Eire Notes" (15 March 1998), Daily News (New York); "Separated from her husband for the last 23 years, Quinn lives quietly in her suburban Leonia home: 'The first and only house I've lived in since coming to America.'"
- Bill Fuller obituary, guardian.co.uk; 9 September 2008; accessed 14 November 2014.
- Re death of son, Michael Fuller, people.com; accessed 4 August 2015.
- Playbill: Jack Arthur Presents Canadiana '64 Around The World In An Evening with Jack Carter and Carmel Quinn, Canadian National Exhibition Toronto (1 January 1964; paperback); ASIN: B0026Y7NUS
- Wait 'til I Tell You (paperback), 1 November 2007; ISBN 978-0976387749
- "Carmel Quinn Sings Her Favorite Irish Songs" (paperback), Box & Cox Publications, Inc.: New York (1942); ASIN: B000JF0TVG