As “Nip/Tuck” begins its final batch of episodes today on FX, series star Dylan Walsh is feeling a curious blend of bittersweet and bemusement.

“We actually finished production back in June, so it feels a little strange,” explains Walsh, 46, who has played beleaguered plastic surgeon Dr. Sean McNamara since the show’s 2003 premiere. “We’ve made peace with the show and moved on, but of course it’s still alive, and closure is still awaiting the audience.”

And although the actor trots out the usual cliches about finding a second home and family on the show’s Paramount soundstages, he admits that he, castmate Julian McMahon and the rest of the creative team were pretty much ready to hang up their scalpels when this season finally wrapped.

“Sean was chronically in a midlife crisis. In fact, it often seemed like he never could get out of it,” Walsh says. “That was really sort of built into the structure of the show, so on one level, it was kind of a relief to say goodbye to him. But the show went on long enough that we all felt like we had ‘done it,’ although obviously it was bittersweet.

“There wasn’t really anything left to pursue, but driving away from Paramount, where we shot it for seven years, for that last time was sad. All the cliches are true: It really does become a home away from home, and it’s a second family. Some of those relationships will keep going, but it won’t be in the same way because we don’t have that context anymore.”

Indeed, the show’s executive producer, Ryan Murphy, says he developed the sunny new Fox musical series “Glee” because he needed something to restore his spirits after working on the dark melodrama of “Nip/Tuck” for seven years. Walsh finds that declaration a little disconcerting, though, given that Murphy was the guy who kept dragging the characters into their dark nights of the soul anytime the show started developing a comic sensibility.

“That darkness was very much his choice,” Walsh points out. “There were entire seasons where we thought that we were starting to edge into a somewhat lighter feel. I remember at the beginning of the fifth season, we had moved to L. A., and we had Oliver Platt and Bradley Cooper, so we felt like we were going to be a little more of a comedic show or at least a lighthearted one. Let’s face it, after we had been so serious for so long, it was time to poke fun at ourselves, and we did. But we didn’t stay there long, because in that same season, it ends with me being stabbed by my manager on the surgery floor. So that was where Ryan always took the show.

“I can see how Ryan would be exhausted by it, because we were all exhausted by it. It just seemed to be that we couldn’t keep it in the comedic zone. It always had to veer back for some reason. That was what the show was. Remember, the pilot episode ended with feeding a carcass to some alligators in a swamp. It always had that darkness, and if we got away from that too long, it felt like we were getting away from the show itself.”

Looking back on the past seasons, Walsh says he tends to remember guest stars rather than individual story arcs, partly because the latter came and went with startling speed.

“Ryan would come and tell you about a story line that would sound like something that would play over a whole season, but that story line would play out in a single episode,” Walsh says, laughing. “They were like sparks; they would flare and be gone.

“I think all the way back to someone like Jill Clayburgh, who played a crazy patient who was stalking Sean for a time. We had an amazing procession of guest stars coming in over the years. Just being able to work with them was wonderful enough, but they all came in with something pretty meaty to act. Rosie O’Donnell had an amazing character, and she played that role so well.”