Reeve Carney was born and raised in the West Village area of Manhattan with his brother Zane and sister Paris. He grew up in a family of musicians and actors: his father, John, was a songwriter for commercials, his mother, Marti, was a singer, actress and a jewelry designer and his great uncle was Academy Award-winning actor Art Carney. He learned how to play the piano at a young age, and began singing for radio and television commercials. At the age of 8, he was chosen to sing in a live performance and video at Lincoln Center's Avery Fisher Hall with Peter, Paul and Mary. Two years later, he recorded a song with a children's choir on Michael Jackson's album, HIStory.
To get a music education, Carney attended the Academy of Music at Alexander Hamilton High School in Los Angeles with his brother, Zane, and future bandmates Aiden Moore and Jon Epcar. He went on to study at the University of Southern California Thornton School of Music, majoring in studio jazz guitar.