Ray Barnett first appeared in fall 2004 at the start of the 11th season. He is a talented doctor struggling with conflicting commitments to the medical profession and his life as a rock musician.
In season 12, the character became involved in a storyline in which, as a flatmate of colleague Neela Rasgotra, he fell in love with her. After being roomates for while, he really got to see the beautiful side of her. These feelings haven proved difficult to deal with as Neela was at the time married to Dr. Michael Gallant, who spent much of his time fighting in the Iraq War. In "If Not Now", Ray's band received an offer to go on a tour to promote themselves. Not willing to let this opportunity pass, Ray asked Kerry Weaver for time off but she announced that he was very valuable for the ER. He eventually managed to convince her but his band chucked him out that day as they felt he was too committed to his job at the hospital. Ray has stayed good friends with Neela. However, since the death of Gallant by a bomb in Iraq, Ray has attempted to become closer to Neela to help cope with the unexpected and tragic loss of her husband. This attempt at closeness has, so far, proved to be unsuccessful as Neela could not cope with losing her husband and her feelings for Ray. He recently realized he missed his chance with Neela with the arrival of John Stamos' character Tony Gates, who has had run-ins with Neela. Ray had a fling with Neela's medical student, who was curious about him. This did not last long because Ray was longing for Neela, who ultimately chose to be with Gates. However, in episode 13.17 , Ray and Neela share a sweet and passionate kiss in Ray's car.

Source: Wikipedia (with some little changes made by me)