In addition to his fourteen solo recordings, Douglas has played on more than 1,600 albums. As a sideman, he has recorded with artists as diverse as Garth Brooks, Ray Charles, Eric Clapton, Phish, Dolly Parton, Susan Ashton, Paul Simon, Mumford & Sons, Keb' Mo', Ricky Skaggs, Elvis Costello, Tommy Emmanuel, James Taylor and Johnny Mathis, as well as performing on the "O Brother, Where Art Thou?" soundtrack. He has collaborated with various groups including The Whites, J.D. Crowe and the New South, The Country Gentlemen, Strength in Numbers, and Elvis Costello's "Sugar Canes".