While attending college, he played with The Star Spangled String Band and The Livingstone Cowboys, and freelanced in the Bleecker Street folk scene.

[5] In the early 1970s, Kenny Kosek was a member of the progressive bluegrass band Country Cooking with Peter Wernick and Tony Trischka on banjo, Russ Barenberg on guitar.

In 1974, Russ Barenberg recorded a solo guitar album with the other members of Country Cooking (Greg Root on mandolin).

While in France, he also played some fiddle parts on French banjo player Jean-Marie Redon [fr]'s first solo album, banjoistiquement votre, and performed at the 1978 International Folk Festival in Courville-sur-Eure, France, both with Bill Keith and Jim Collier, and with his former fellow musicians Tony Trischka and Russ Barenberg, as well as with French mandolin player Christian Seguret [fr] and bassist Lionel Wendling, who joined the two bands.

[7] From the mid-1970s onwards, Kenny Kosek also worked as a studio musician7, recording with Steve Goodman (1976),[8] Chaka Kahn (en),[9] James Taylor (1985), David Byrne (1990),[10] Boy George,[1] Willie Nelson, Tom Chapin, Doug Sahm, Leonard Cohen, and John Denver.

[1] In the eighties, Kenny Kosek replaced Richard Greene on the fiddle in the “New Blue Velvet Band”, with Jim Rooney, Eric Weissberg and Bill Keith, to tour major folk festivals in Canada, continental Europe, Great Britain, Ireland and the northeastern United States.

[13] This short collaboration helped Kenny Kosek to make a name for himself beyond studio and bluegrass circles, particularly with the Deadhead (fans of the Grateful Dead).

[16] At the end of 2005 (November–December), he took part, a guitar and fiddle player, in the Broadway show (Promenade Theatre) : Almost Heaven: The Songs of John Denver.

[20] In addition to performing music, Kosek has appeared in many dramatic productions: in the movies They All Laughed and The Stepford Wives; on Broadway, in The Robber Bridegroom, Platinum, Play Me A Country Song, Foxfire, Big River, Jerry Garcia on Broadway and Footloose; and off-Broadway, in Feast Here Tonight, Das Barbecü, That and the Cup of Tea, A Celtic Christmas, Lost Highway, and Picon Pie.