While performing in a Washington D.C. coffeehouse, she was discovered by former Byrds member Chris Hillman, who recommended her to Gram Parsons for his first solo album, `GP`. Harris toured as a member of Parsons` band, The Flying Burrito Brothers, in 1973, and recorded on their album `Grievous Angel`. After Parsons died of overdose, Harris was devastated and wrote her most well-known song `Boulder to Birmingham`. Three more of their duets were included on another posthumous Parsons album, `Sleepless Nights`, in 1976.
Has collaborated on the albums of Linda Ronstadt, Dolly Parton, Vince Gill, Neil Young, Bob Dylan (her vocals are prominently featured on his 1975 album Desire), Roy Orbison, Ryan Adams, Elvis Costello, Bright Eyes, Mark Knopfler, Anne Murray, and Willie Nelson. Performed duets on a Gram Parsons tribute album with Beck, Sheryl Crow and The Pretenders.