Duncan was born in
Quantico, Virginia, and raised in
Santa Paula, California, where he played in the school band. He is married with three children. Duncan has been a member of the
Nashville Bluegrass Band since 1985. He also works as a
session musician and has played with numerous well-known performers, including
George Strait,
Dolly Parton,
Guy Clark,
Reba McEntire, and
Barbra Streisand. In 2006, he toured with the
Mark Knopfler–
Emmylou Harris Roadrunning tour, and he appears on their
All the Roadrunning and
Real Live Roadrunning albums. In 2008, he joined
Robert Plant and
Alison Krauss on the tour for their critically acclaimed album
Raising Sand. He appeared on
Transatlantic Sessions Series 4 broadcast by the BBC in September/October 2009. In 2011, Duncan collaborated with cellist
Yo-Yo Ma, bassist
Edgar Meyer, mandolinist
Chris Thile, and singer
Aoife O'Donovan on the album
The Goat Rodeo Sessions. The album debuted at number one on the
Billboard Classical, Classical Crossover, and Bluegrass charts and reached number eighteen on the
Billboard 200. It also won the
Grammy Award for Best Folk Album and the
Grammy Award for Best Engineered Album, Non-Classical in 2013. In 2013, Duncan accompanied
Diana Krall as a sideman on her
Glad Rag Doll tour. In 2015 Duncan appeared on one of the tracks from the Jericho Summer album
Night Train. Playing jazz on the violin, Duncan again toured with Diana Krall in 2018. In 2020, Duncan once again collaborated with Ma, Meyer, Thile, and O'Donovan, releasing the album
Not Our First Goat Rodeo. In April 2025, Duncan joined
Alison Krauss & Union Station on tour as a fiddle player. ==Awards==