The protesters accuse Sudanese President Omar al-Bashir of provoking a humanitarian crisis and blocking food and aid from entering the Nuba Mountains in the county's border region with South Sudan.
Clooney, his father, Nick Clooney, and others including Democratic U.S. Rep. Jim Moran of Virginia, NAACP President Ben Jealous and Martin Luther King III, were arrested after being warned three times not to cross a police line outside the embassy. They were handcuffed and placed into a U.S. Secret Service van.
The arrest came after Clooney met this week with Obama, testified in the Senate and attended a state dinner for British Prime Minister David Cameron.
Clooney told The Associated Press before he was arrested that he can only hope to draw attention to the crisis in Sudan but that he doesn't know if any progress has been made. He said he was impressed, though, with Obama's engagement on the issue.
"It's amazing to sit down with a world leader who knows all of the intricacies of what's going on in Sudan," he said.
The actor said he asked Obama to involve China more in pushing for a solution in Sudan. He said international leaders need to "follow the money" flowing to Sudan's leaders to expose corruption.
"This is a moment where we have a chance to do something because if we don't, in the next three to four months, there's going to be a real humanitarian disaster," Clooney said before his arrest.
"It's such a silly thought to think you're actually succeeding in any of this," he said. "But if it's loud enough and you keep making it loud enough at the very least people will know about it, and you can't say we didn't know. That's the first step."