Though she began her recording career singing folk music with her band the Stone Poneys in the mid- to late-1960s, Ronstadt has been credited as a solo artist with singing in extraordinarily diverse genres ranging from more traditional country to rhythm & blues and including, among others, new wave, opera and mariachi. In its biography on her artist page, Rolling Stone's Web site reads, "she doesn't succeed at every style she attempts, but that hasn't stopped her from exploring new avenues…. check out her Trio recordings with Emmylou Harris and Dolly Parton; they are essential listening for fans of any kind of music."

Ronstadt's success is, in part, connected with the influence she had on or the influence she received from artists such as Harris, Parton, J.D. Souther, The Eagles, Andrew Gold, Kate and Anna McGarrigle, Paul Simon, Mark Goldenberg, Karla Bonoff, Aaron Neville, James Taylor, Warren Zevon, Maria Muldaur, Nicolette Larson and Elvis Costello. Her reputation throughout the 1970s was of working with some of the most well-respected musicians in contemporary rock music but also of having her own strong sense of discipline.

Some of Ronstadt's better known hits are covers of songs by Zevon, Costello, Souther, the Rolling Stones, Mel Tillis, Tom Petty & the Heartbreakers, the Everly Brothers, George Jones, the Flying Burrito Brothers, Little Feat, Neil Young, the Miracles, Betty Everett and Buddy Holly and the Crickets.

Her work with producer Peter Asher from 1974 through the 1980s resulted in her greatest commercial success. By the end of the 1970s, Ronstadt had collected eight gold and four platinum certifications for her albums, a considerable feat at the time. She was often referred to then as the "highest paid woman in rock," able to command sell-out concerts in arenas hosting tens of thousands of fans despite a reputed stage shyness. In 1977, she appeared on the cover of Time magazine under the banner "Torchy Rock." Ronstadt has appeared on the cover of Rolling Stone magazine six times.

Ronstadt's success was also propelled in the late 1970s by a relationship with then-Governor Jerry Brown of California, a Democratic presidential hopeful. Their romance became the subject of many magazine articles and a Newsweek cover in April 1979. In the 1980s, Ronstadt had a long relationship with director George Lucas. Despite association with several male celebrities over the years, she has never married, but she adopted two children.

As of the end of 2005, Ronstadt has earned three No. 1 albums on the Billboard 200, a No. 1 single on the Billboard Hot 100, 10 Top 10 albums and 10 Top 10 singles. Her highest-selling studio albums are her 1983 set What's New and her 1989 release Cry Like a Rainstorm, Howl Like the Wind, each certified by the Recording Industry Association of America for 3 million units shipped. Her highest-selling album of all time is the 1976 Greatest Hits compilation, certified seven times platinum in 2001. In all, Ronstadt has been certified by the RIAA for 30 million copies of singles and albums shipped and has won 10 Grammy Awards in fields including pop, country, tropical Latin and Mexican-American.