More Mr. Nice Guy : Chris O’Donnell is having quite a year. First ‘Circle of Friends,’ then ‘Mad Love,’ and now ‘Batman Forever.’ How can the Caped Crusader’s high-flying sidekick be so down-to-earth?

For the Great Robin Hunt, casting directors for “Batman Forever” trekked around the coun try. They looked at about 6,000 aspiring sidekicks ranging in age from 14 to 25, from a variety of ethnicities, religions and economic levels. In some cities, the casting directors held mass auditions; in others, they rooted around martial arts schools and community centers.

In the end, it was a no-brainer: Go with the proven talent.

Chris O’Donnell, who, with no acting background, shined in Paul Brickman’s “Men Don’t Leave,” held his own against Al Pacino in “Scent of a Woman” and is currently basking in accolades for his recent performances in “Circle of Friends” and “Mad Love,” was recruited, without so much as an audition, as the fledgling Robin.

Still, O’Donnell was momentarily circumspect before flying into the Bat’s radar.

“I didn’t get totally swept away,” he says during an interview at Beverly Hills’ Peninsula Hotel. “I did step back there for a second, if maybe only for a second. I was talking about it and one of my friends said, ‘Are you kidding me? This is “Batman,” how can you not do it?’ As opposed to the usual discussions we have about movies: ‘Will this help me or hurt me?’ ”

“Batman Forever,” which opens Friday, is poised to revive the series after the disappointment surrounding “Batman Returns.” Here, the Dark Knight’s sensibility is melded slightly with the old Caped Crusader’s, as director Joel Schumacher jettisons some of the monochromatic Sturm und Drang that was the touchstone of Tim Burton’s movies in favor of a more assertively colorful lunacy.

“This is one of those movies that it’s as fun to be on the set and watch them make it as it is to be in it,” O’Donnell says. “These sets and these gadgets and cars and costumes, it’s just amazing.”

Here, Batman (Val Kilmer) compares costumes and arsenals with Two-Face (Tommy Lee Jones), who wants him dead, and Riddler (Jim Carrey), who is happier simply to humiliate him. Batman--and Bruce Wayne--flirt with Dr. Chase Meridian (Nicole Kidman), who’s a deviant psychologist in every sense of the term, and Wayne adopts Dick Grayson, a young acrobat whose family was cut down by Two-Face and who seeks revenge as Robin.

But this is not your father’s Robin. Ditching the yellow cape and green booties of the old comic book and TV series, O’Donnell cavorts about in a high-tech rubber suit (which reportedly gave “Batman” creator Bob Kane fits) with built-in nipples and an extravagant codpiece.

“It was a running joke,” recalls O’Donnell, who turns 25 on June 26. “They’d say, ‘Chris, we need you and your codpiece on the set.’ ”

Schumacher says of his Boy Wonder, “I’ve kept my eye on him, but never had a role for him really. He was great in ‘Men Don’t Leave,’ then he had to carry ‘Scent of a Woman.’ Like Tom Cruise in ‘Rain Man,’ Chris did extraordinary work in an unsung role. Not to take anything away from Al Pacino and Dustin Hoffman, but they have so much sound and fury going on for them--accents and infirmities, suicidal tendencies and madness--and you get to be reactor to all that. It’s easier in a way to play an aberrant person than a normal person, where you have to dig much closer to your being and do very controlled acting. Many times in this business, the most restrained acting gets the least attention.”

‘B atman Forever,” however, hardly calls for quiet Method acting--the reason there are so many sets in this movie is apparently because there are so many actors chewing them up. “I had a number of scenes with Tommy [Lee Jones],” O’Donnell says, “and you would definitely be drowned out by that.”

Schumacher adds: “There are many young people who have been spoiled--they’re beautiful, talented and have made a fortune at a young age. They’re very talented, but they’re lazy, they come in hung over, unprepared, they don’t know their lines. Chris is the exact opposite of that. He’s always on time, always ready, always . He worked-out strenuously for this part, which was demanding physically. He works very hard: He’d do 100 takes, if I would let him, on every scene.

“And he has no respect for me whatsoever. He would mock me, make fun of me, all day long.”

Actually, O’Donnell has plenty of respect for Schumacher: He’d want the director in place before considering any sequels. “The guy is just a machine. I don’t know how he does it; he just works nonstop,” O’Donnell says. “He’s always in a good mood. He was so great on this set, because on a film this big, there’s a lot of money on the line so there can be a lot of stress, you’re really under the gun to perform. He keeps the atmosphere great.”

O’Donnell recalls a prank Schumacher pulled on him, when shooting a scene in which Riddler has trapped Robin in a giant test tube.

“I get up in this thing, my hands are bound behind me, I’m gagged, my ankles are tied, I’m suspended in this little pod like I’m in ‘Spinal Tap’ or something, and all of the sudden, they raise me up, you can barely breathe in this thing, and Joel says, ‘That’s lunch! One hour!’ and everyone left the set,” O’Donnell says, a grin fading into a grimace. “I knew it was a joke, but they kind of left for a few extra minutes I didn’t like.”

And there was that incident with the Batmobile. Schumacher delights in describing how O’Donnell wrought havoc with the muscle car to end all muscle cars. O’Donnell, naturally, defends himself by evoking the “Brady Bunch.”

“If Joel and I had a little driving contest with the Batmobile, with the little egg on the cone like Marcia and Greg, I guarantee you I will win. But I will admit that I put a few minor scrapes on parts of the Batmobile. It is not easy to drive, because you can’t see out of it. They have to light the inside so you have neon lights in your face, so you can’t see out because it’s so bright inside and the brake pedal is way up here and the gas down there--it’s cool, though.”

Schumacher concludes: “There is an amazing clarity and honesty and innocence--not naivete, but there’s an integrity to him. On one hand, he’s clean-cut and has these wholesome looks, but he’s also a Chi caaa go guy--down-to-earth, unpretentious. He has street savvy and strength, and doesn’t seem like some coddled kid from some rarefied atmosphere.”

That’s O’Donnell’s rep: the regular guy who made very good. He avoids, as much as he can, L.A. and its chichi trappings, has a good work ethic and apparently has never even heard the phrase “copping an attitude.”

Frank Price, producer of the Irish coming-of-age tale “Circle of Friends,” is happy to muscle for position at the front of the O’Donnell bandwagon.

“He was just wonderful in a situation that could’ve turned out quite differently,” Price says. “Here’s this young actor, a budding American star, who comes into a picture that is cast totally with Europeans. Clearly he’s getting paid more; he’s the star. That can create resentment. What was terrific about it was how unassuming he is and was, how friendly. He wasn’t doing the star thing. Everyone liked him. He’s thoughtful, considerate, just a very decent guy.”

As a measure of O’Donnell’s decency, Price points out, “[Minnie Driver’s character] is the one you’re rooting for, and Chris is the guy who breaks her heart. And he was able to do this in a way that you still cared very much for him, you still liked him and still wanted her to get with him. That takes real appeal on screen, and real ability. It’s impressive to find a guy with that kind of good grounding and instincts.”

O ‘Donnell credits said ground ing to his parents. The youn gest of seven children who grew up in Chicago--where he still lives--he first fell into modeling and bit parts in local commercials, donning pajamas for Sears’ flyers and serving up a burger to Michael Jordan in a McDonald’s spot. Simply put, it was easy money.

“I’d go downtown for an hour, they pay me 65 bucks,” he recalls. “It’s unbelievable. When you’re 15 and you have $65 in your pocket, you’re doing pretty well.”

When his agent told him that casting directors for the film “Men Don’t Leave” wanted to see him, he blew off a couple of auditions, he says, because “I seemed like such a long shot. I’d been to auditions before, and you just sit in traffic for an hour to get downtown. You get down there, go in the room and they say, ‘No, you’re not right. Next.’ I thought, ‘Forget that!’ Until they finally said, ‘We’re going to fly you to New York so you can read with Jessica Lange.’ When they said that, I thought, ‘Oh, God. This could be a pretty great deal.’ ”

A few other small roles followed, but it wasn’t until “Scent of a Woman” that O’Donnell decided that acting could be more than just a well-paying lark.

“I worked real hard preparing for it, got really focused on it,” he says. “I said, ‘I got to get this.’ And when I got it, it was just a really satisfying feeling. I felt [with] ‘Men Don’t Leave’ [that] maybe part of me getting the part was being this regular kid they cast. But ‘Scent of a Woman,’ I was up against everybody else, and I got it because I did a good audition. That gave me a lot of confidence.” Pacino won the Oscar, but O’Donnell more than acquitted himself, garnering a Golden Globe nomination for best supporting actor.

Then came his first real hit, the loopily unliterary “Three Musketeers,” which may be better recalled in Europe for the wide swath co-stars Charlie Sheen and Kiefer Sutherland cut across the continent.

“These stories were so blown out of proportion,” O’Donnell says. “A group of my friends came over, and every time I’d be leaving at 6 in the morning to go to work, they’d be stumbling in. They had a wilder time than any of us. Everyone thinks Charlie and Kiefer are so wild, but give their salaries to some of my buddies, I guarantee you you’ll see some really crazy stuff going on.”

“Circle of Friends” and “Mad Love” hit theaters just before “Batman Forever.” O’Donnell calls the former, a modest romantic comedy that became a more-than-modest hit, “the best experience I’ve had on a film, just for the pure enjoyment of being on a set.”

Despite mixed reviews, “Mad Love” held its own at the box office against the much more expensive and hyped Keanu Reeves thriller “Johnny Mnemonic,” a testament to O’Donnell’s growing star power.

Now, Robin may help O’Donnell soar to A-level status. He’s prepared, but that doesn’t mean he’s not approaching it with a little trepidation.

“As much as you have to take advantage of the situation, you have to be smart about it,” he says. “You can’t just jump into a bunch of things because everyone’s offering them. The thing that’s tricky is that now I’m getting projects offered to me at such an earlier stage--directors aren’t even set, and there’s not a finished script. I’ve never been in that situation before. They want you to commit so early.

“It’s made me realize why sometimes you see an actor you really like in a film and think, ‘God, why did he do that film?’ Now I realize, he probably saw a script, and was probably the first person attached, thinking he’d be with this director and that actor, and things fell apart, but he was locked in. It’s scary. It’s my career here, and I’d like to keep doing this for a long time.”

Despite having spent the past few years showing up in dashing photos in publications ranging from Seventeen to GQ, the upcoming onus of being a leading man is, O’Donnell says, “a new situation for me. It’s tough, because I’m flattered when people want to work with me, but you have to step back and think about it before you get swept away in the excitement. I can feel people bearing down on my agents and people around me. You definitely feel studios trying to push things through and lock things in.”

Instead, O’Donnell is biding his time, waiting for the perfect project as a follow-up to “Batman Forever.” “You’d think that if you’ve had some successful films, you could sit back and relax,” he says, “but then it’s even more confusing.”*