Profile : What’s Up, Doc? : GEORGE CLOONEY RETURNS TO THE SCENE OF A FAMILIAR SET

George Clooney may be the only actor who has starred in two TV series with the same name.

Nine years ago, Clooney got his big break on the short-lived CBS comedy series “E/R,” which was set in a Chicago hospital’s emergency room. Clooney played a wiseacre medical intern named Ace.

“That was a fun series,” recalls Clooney, who is the son of “American Movie Classics” host Nick Clooney, nephew of singer Rosemary Clooney and cousin of actor Miguel Ferrer.

These days, Clooney is back in his green scrubs as a regular on NBC’s highly touted Thursday- night series “ER,” which, as was “E/R,” is set in a Chicago emergency room. This time around Clooney has graduated to full-fledged doctor: Douglas Ross, a charming pediatric resident who handles the pressures of the ER by drinking during his off hours.

“ER,” which was created by “Jurassic Park’s” Dr. Michael Crichton and John Wells (“China Beach”), is Clooney’s eighth TV series.

Disarmingly charming, Clooney loves to joke about his rather dismal series track record and seems to relish putting down his acting ability.

“I did some bad (series),” says Clooney, relaxing in his trailer at the Warner Bros. lot where “ER” films. “ ‘Baby Talk’ was bad. I quit that. ‘Sunset Beat’ wasn’t necessarily a great show. I played an undercover cop on a Harley during the day, and by night I was a rock star. We did 13 and they aired two before they canceled us. ‘Bodies of Evidence’ wasn’t a bad show. ‘Roseanne’--you can’t forget the one good one I had in my career.”

“Roseanne” wasn’t the only “good” series though. Last season, Clooney played Sela Ward’s love interest on NBC’s long-running “Sisters.” The season ended with the two lovers on a plane that was about to crash. Clooney stays mum on whether he survives the crash. “I just shot three episodes that take care of my little problem on ‘Sisters,’ ” Clooney says, smiling.

“ ‘Sisters,’ he says, “was a grand show to be on. Everybody is real nice. I love all of those girls. We really had a fun time. But the show is called ‘Sisters’ and it will always be called ‘Sisters.’ I will never be a sister . I put on a long red wig and tried it, and it didn’t work.”

Clooney, who has had a development deal at Warners, heard about “ER” through the studio’s grapevine and quickly pursued the showy role of Dr. Ross. “When you’re under contract they usually just say, ‘Would you like to do this?’ This is one I wanted really badly and read for this role specifically. He’s a bit of a womanizer. He has a real drinking problem, and any type of work with Steven Spielberg (Spielberg’s Amblin Television is one of the producers), Michael Crichton and John Wells, you have got to jump. It’s a great break for me especially because I’m not really known for doing good television. You don’t look at me and say, ‘Hey, he’s great.’ All kidding aside, I’ve been really bad in a lot of TV series I’ve done over the years. I’ve been good in some and I’m proud of the ones I have been good in. You learn as you get older how to make things work.”

“George was pretty well-connected around the studio,” recalls Wells, who also is executive producer. “He refers to it as his lot. He told me what he wanted to do was this part. He told me, ‘Nobody else can have it.’ After the pilot did get a pickup, he told me, ‘I’m coming in on Friday and I’m going to get this part.’ So he came in and he memorized one of the scenes: the scene (in the pilot) with the abusive mother. He was the first and only person we saw for the role. He just came in and read it. He was very good in it and we said, ‘You got it.’ ”

Adds Wells: “George is a very funny guy. He is a great presence on the set. He keeps us all in stitches.”

The series also has become a family affair for Clooney. Ferrer guests as a cancer patient in the premiere episode, and Aunt Rosemary will appear in an upcoming show.

Clooney says he doesn’t want Dr. Ross to become the Arnie Becker of “ER.” “I walk a tightrope on this show. I didn’t want to be the womanizing, ‘Hey sweetheart, baby’ kind of guy. I don’t want to be the guy who gets hit in the face with a pie and everybody goes, ‘Yeah, that’s great.’ This guy may earnestly chase women, but you get to see some of the process involved.”

So is Dr. Ross the best role he’s ever had?

“You want me to be honest or modest?” Clooney asks. “When you are doing good writing or working with good actors and good directors, it’s difficult to be bad. I’m in a great position. I’m in a show that every actor would rip out their eyes to be in. I’ve a showcase part and I do a good job in it.”

Clooney doesn’t seem fazed that “ER” is going head to head on Thursday nights with “Chicago Hope,” CBS’ new medical series from “Picket Fences” creator David E. Kelley.

“It’s a wonderful series and if I were on it, I would be extremely proud,” he says of “Chicago Hope.” “I couldn’t say anything bad about it if I wanted to. And I certainly want to. But I still like our chances. I love our chances.”

Another mischievous grin dances across Clooney’s face. “We are doing something neat which ‘Chicago Hope’ won’t do: Everybody who watches the show gets a free car,” he jokes. “I think that’s a neat thing. We’re proud of that fact.”

A two-hour “ER” premieres Monday at 9 p.m. and moves to its regular time slot Thursday at 10 p.m. on NBC.