James Christopher Carmack (born December 22, 1980) is an American actor, singer, and former fashion model. He is known for his roles in three popular television shows—the teen drama series The O.C. (2003–2004) as Luke Ward, the country music drama Nashville as Will Lexington (2012–2018), and the medical drama Grey's Anatomy (2018–present) as Dr. Atticus Lincoln.

Carmack has also appeared in films, including The Butterfly Effect 3: Revelations, Into the Blue 2: The Reef, Love Wrecked, Beauty & the Briefcase and Alpha and Omega.

Early life and education
Carmack was born in Washington, D.C., and grew up in Derwood, Maryland. He has a brother and a sister. As a young boy, he enjoyed participating in all types of sports: baseball, basketball, football, and wrestling. Carmack was also a longtime counselor at Seneca Creek Day Camp, known for singing the original "Rocko the Lazy Moth" and "Ode to Salpino" among other favorites. At Magruder High School, however; his attentions turned to theater and he began working on three productions per year, on-stage and off, in addition to competing in numerous drama festivals.