What happened to his career?
I remember in the mid-to-late 90s this guy was hot shit. He was a popular up-and-comer, like Keanu Reeves or Matt Damon or Matthew McConaughey. I remember him from films like Scent of a Woman, School Ties, Vertical Limit and, yes of course, Batman & Robin.
School Ties is particularly interesting because it's like a Who's Who of actors of that generation: O'Donnell, Brendan Fraser, Matt Damon and Ben Affleck all appear, among others. But all of those guys went on to bigger and better careers.
Today, O'Donnell is still working, but as a character on NCIS: Los Angeles. An NCIS spin-off is where careers go, not to die, but to shuffle forward like an inanimate corpse. It's a paycheck, but is it really respectable?
The last film I saw him in was Kit Kittridge: An American Girl. It was an enjoyable little family film and he did a fine job in it. But that was 10 years ago.