Debralee Scott was born in 1953 in Elizabeth, New Jersey, as the youngest of four daughters born to William Henry Scott, Jr. (March 1, 1914, Scranton, Pennsylvania - September 17, 1993, Scranton, Pennsylvania) and Marion Jones (February 11, 1916, Scranton, Pennsylvania - October 1993, Pittston, Pennsylvania); Debralee's older sisters were producer Carol Ann Scott (later known as Scott Bushnell) and Beverly Hills talent manager Jerilyn Scott, and Ardith Lynn Scott, who had died in infancy. When Scott's sisters were young adults, they relocated from Elizabeth, New Jersey, to San Francisco, California.

Scott was raised in Elizabeth, New Jersey, and Stroudsburg, Pennsylvania, where she was a high school cheerleader. In Elizabeth, she worked at a movie theater while she attended a Greek-Latin course at Stroudsburg High School. In 1969, the 16-year-old Scott joined her older sisters in San Francisco; she graduated from Galileo Academy of Science and Technology in 1971 and started acting at the American Conservatory Theater.

Scott's very first acting job was in 1971 as an uncredited extra in "Dirty Harry (1971)"; she played the nude corpse of Ann Mary Deacon, a 14-year-old girl who was kidnapped, raped, and buried alive by the Scorpio Killer. Following this, Scott played the girlfriend of Harrison Ford in "American Graffiti (1973)" ("Ain't he neat?" her character says).

In the mid 1970s, Scott relocated to Los Angeles, California, and got an agent. Scott played semi-recurring character Rosalie 'Hotsy' Totsy on Welcome Back, Kotter (1975). At the age of 22, Scott starred in Mary Hartman, Mary Hartman (1976) as the titular character's younger sister Cathy and reprised the role for the show's sequel Forever Fernwood (1977). After "Forever Fernwood" ended, Scott became a host for celebrity quiz game shows, including The $10,000 Pyramid (1973), Super Password (1984), and Match Game (1973). Scott also acted in Pandemonium (1982) and Police Academy (1984). She was in relationships with Desi Arnaz Jr., Micky Dolenz, Richard Dreyfuss, Jonathan Frakes, Peter P. Lucia Jr., Neal Schon, and Ringo Starr.

In the mid 1990s, Scott became a talent manager for the agency Empowered Artists. On December 15, 1995, she went to the Greenwich Village bar Hogs & Heifers and met her future fiancé, John Dennis Levi, an NYPD officer working for the Port Authority of New York and New Jersey. Over time, Scott lived at Levi's house in Brooklyn, New York, with his mother Joanne Priavity. In 2001, while on a cross-country trip, Levi proposed to Scott at a hotel in Winslow, Arizona, and she accepted. They planned to get married in March 2002, but Levi was killed in the South Tower of the World Trade Center during the September 11 attacks. Heartbroken, Scott became an alcoholic and developed cirrhosis of the liver.

In March 2005, Scott relocated from Brooklyn to Fernandina Beach, Florida, to care for her eldest sister, Carol Ann, who was suffering from emphysema and heart problems. One day, she collapsed and fell into a coma for several days. It was not known what caused the coma. On March 31, 2005, Scott woke up in the hospital, underwent eye surgery, and was released two days later on her birthday, appearing to be fine. Three days later, on April 5, 2005, Scott lay down to take a nap and died in her sleep at the age of 52. An autopsy was performed, but no specific cause of death was listed, and Scott was cremated.