CHAMPAIGN -- In the hit Coen brothers' movie "O Brother, Where Art Thou?", actor Tim Blake Nelson makes an indelible impression as Delmar O'Donnell, a major doofus and an escapee from a chain gang.

In fact, he's so convincing you might think Nelson is, well, intellectually challenged.

Not so.

A Latinist, he graduated from Brown University with a degree in classics. (The Coen brothers once said Nelson was the only cast member in "O Brother" who had read Homer's "Odyssey," on which the movie is based.) He studied acting at Juilliard.

He doesn't just act; he writes, directs and sings. He sings well enough that his voice was not dubbed in the song "In the Jailhouse Now" on the "O Brother" soundtrack, which won the Grammy for Album of the Year in 2001.

"The others are dubbed," Nelson said last week in a telephone interview. "George (Clooney) is a good singer George can carry a tune. I think with that song, 'Man of Constant Sorrow,' which is pretty demanding vocally, they really needed it dubbed. It's also the song that takes the nation by storm so they really needed a voice that was irrefutable.

"I think the bar was a little higher for George than for me."

Nelson sang as he grew up in Tulsa, Okla., and at Juilliard in New York he took singing classes, though he said he does not have the vocal training necessary for Broadway musical theater. But he's good enough to sing in avant-garde shows, he added.

Nelson will appear in the role of director when he appears in person at Roger Ebert's Film Festival on Saturday evening with "Leaves of Grass," the fourth feature movie that he directed. He also wrote it and plays Bolger in the movie.

"Tim Blake Nelson is well-known as an actor, but deserves equal fame as a director," Ebert wrote for the Ebertfest 2011 program. "I've admired every one of his films, particularly the harrowing Holocaust drama 'The Grey Zone' (2001). Now comes 'Leaves of Grass,' which I saw at Toronto 2009 and found truly remarkable.

"Yes, it has a 'double role' for Edward Norton, but this isn't an occasion for special effects; it's a collaboration by Norton and Nelson to make twins who are distinguishable from the inside out. The movie is funny, heartfelt, surprising and a virtuoso example of overcoming technical difficulties with its brilliance of vision."

Most personal film

In the movie, Norton plays twin brothers, one a drug dealer in Tulsa and the other a professor in the Northeast who returns to their hometown because he believes his twin has been murdered.

He wasn't, and the professor gets caught up in the dangers of the drug trade.

"Though it has an outlandish plot it's a very personal movie," Nelson said. "I pulled on a lot of what I experienced when I grew up in Oklahoma the examination of the Jewish community there, the dichotomy between the son who stays and the son who leaves, the struggle and appreciation of a place where you've grown up and the desire to leave it. These are issues that are very personal to me."

He grew up one of four children to a petroleum geologist and a mother who is an activist, philanthropist and now chair of the Tulsa Housing Authority. His parents are divorced; his father now lives in Connecticut.

Like most people who become professional actors, Nelson as a child liked trying on different roles as a way of playing and entertaining himself. "Even in conversations I was putting on voices, and people encouraged me to try it out in school plays," he said.

The seminal moment for his career, though, came late in his junior year at Brown, when his mother visited him on campus. She asked her son what he planned to do that summer.

"I told her, 'I think I'll come back to Tulsa,'" he remembered. "She said, 'What do you want to do with your life?' I said, 'I want to pursue classics and maybe be a professor.' She said, 'That would be great, but you did enjoy acting in high school, and now is the time you can try anything and it doesn't cost you and you don't have to have a job to support a family or a spouse. You know you're going to be out of college next year. Why don't you get involved in summer theater?'

"I did, and thanks to my mother I never looked back in terms of pursuing a career in the arts."

Quoting Roman poets

He had majored in classics not necessarily with the goal of becoming a classicist, but instead for the broad-based foundation it would give him in Western culture, and because he had enjoyed studying Latin in high school.

"I'm really glad I did that," he said. "Roger and I on occasion have sent emails to each other quoting Latin poets. Maybe somehow, way back then, I knew I would need to be quoting Roman poets to Roger Ebert."

After graduating from Brown, Nelson spent the next four years at Juilliard, studying acting. Again, he had his reasons for doing that.

"I wasn't walking around with a beautiful young face that the world was waiting to see up on screen or on stage," he said. "I calculated accurately that between the ages of 22 and 26 I wasn't really going to miss out on great work opportunities and that it would be better for me as I got older to be a character actor. I really needed formal acting training so I thought I would get the most regimented training in that at Juilliard."

And that's where he met the woman who became his wife. Lisa Benaveides, also an actor, now teaches at the Tisch School of the Arts at New York University. She and Nelson will be married 17 years in June; they have three sons, ages 12, 8 and 6.

They live in New York, and to support his family, Nelson takes more remunerative screen and TV jobs but remains active in theater, mainly as a member of theater boards.

Eyes wide open

As an actor, he believes he's best known depending on what region of the country he happens to be visiting as Delmar in "O Brother, Where Art Thou?"; Dr. Pendaski in "Holes" (2003), an Ebertfest 2007 selection; Samuel Sterns in "The Incredible Hulk" (2008); and Gideon in Steven Spielberg's "Minority Report" (2002).

In one interview, Nelson said when he was working on "Minority Report" he was impressed by how Spielberg could perform nearly every job on a movie set.

As a director himself, Nelson said he's learned a great deal from every director he's worked with, from beginners to masters.

"I know that's vapid and diplomatic but it really is true," he said. "There's so much to directing. I've learned a great deal even from directors who directed fewer films than I have, with fractional budgets. Just because each film is different and has different demands.

"If your eyes are open and your nose isn't pointed up in the air, then there really is something to learn from everyone. That really has been my experience; I mean that with all earnestness."

His big year

Nelson must have learned a lot recently. He has acted in six movies expected to be released this or next year, though two have yet to find a distributor.

"All of them are good, I think," he said. "I still haven't seen all of them. The scripts were really compelling. It's just one of those lucky periods in my life where I seem to be going from one movie to another, which is always reassuring you can remember that that happened when you're going through a fallow period."

Two of the movies are big-budget "Everybody Loves Whales," directed by Ken Kwapis, and "The Big Year," directed by David Frankel.

Nelson said "Whales" examines the attempt in 1988 to save three California gray whales stranded in ice off Point Barrow, Alaska.

It's based on the book, "Freeing The Whales How the Media Created the World's Greatest Non-Event" by Tom Rose.

"The media descends on the place and turns it into a huge story that travels the globe," Nelson said. "Suddenly these whales that are going to die, in a routine way, are saved at an expense of tens of millions of dollars. The U.S. government, the Soviets all get involved. It examines our compulsion to save animals and how the media can prey on that to create a story."

"The Big Year" is about three bird watchers who compete at a prestigious annual event to spot the rarest birds in North America. It stars Jack Black, Steve Martin and Owen Wilson.

"It's sort of a PG comedy, not R-rated," Nelson said. "It's very tame and gentle. That's actually high praise."

In that, Nelson plays a member of a group of eccentric bird watchers played by Anjelica Huston, Jim Parsons, Brian Dennehy and Dianne Wiest.

In the TV series "Chaos," Nelson played a role unusual for him, that of Casey Malick, the sarcastic "human weapon" in a group of rogue CIA operatives. After our interview, CBS pulled the new action-comedy, which had run only three weeks and was shot entirely in Vancouver. The show is on hiatus and could return later.

Directing a challenge

Nelson said the Malick role is challenging, but the most challenging thing he does is direct.

"It really calls on every thing you have, both physically and mentally, and spiritually and psychologically. I can't imagine a more dimensional experience than what it is to direct a movie that you've also written."

As writer, Nelson is now at work changing the ending of the latest movie he has written and will direct "The Gyre." It's based on a story he told his three sons.

"That's a big fantasy movie I'd like to make next year," he said. "There's something else I'm writing but I don't know where that's headed. I don't know what it's going to be yet, something on screen, or on stage."

Because of his busy schedule, Nelson will be at Ebertfest less than 24 hours; he has to be in New York next Monday night to host a fundraiser for the Soho Repertory Theater he's on its board of directors.

He would like to stay here longer.

"I love Roger. I really want to be able to see the other films. It's heartbreaking that I'm going to be in and out."