Clooney, his father Nick and other anti-Sudan activists ignored three police warnings to leave the embassy grounds and were led away to a Secret Service van in plastic handcuffs, a Reuters journalist covering the demonstration said.
Clooney told a Senate hearing on Thursday that Washington must get tough on Sudan President Omar al-Bashir and two other Sudanese officials indicted by the International Criminal Court as part of an investigation into atrocities in Darfur from August 2003 to March 2004.
Clooney said violence between Sudanese soldiers and rebels aligned with South Sudan in border areas including South Kordofan's Nuba mountains involved repeated attacks on unarmed civilians who already face a serious humanitarian crisis.
"They are proving themselves to be the greatest war criminals of this century, by far," Clooney told the Senate panel, calling for increased U.S. efforts to find and freeze offshore accounts of indicted Sudanese officials.
Clooney, who recently returned from the Nuba mountains region, showed senators a video detailing the grim humanitarian conditions of a Sudan population fighting for survival while under attacks from bombs and missiles.
On Friday, Clooney said he was protesting Sudan's efforts to block humanitarian aid from reaching a volatile border region where its army is fighting rebels aligned with South Sudan.
He had been widely expected to provoke police into arresting him. Clooney's hands were tied, and he and other protesters were quietly and peacefully led away by police.
Sudan and South Sudan have stepped back from the brink of all-out confrontation and the world community should seize on this to win humanitarian access to food-starved regions and press for broader reconciliation, senior US officials said on Wednesday.
Princeton Lyman, the top Obama administration official for Sudan, said Tuesday's announcement that Sudan President Omar al-Bashir would visit South Sudan in coming weeks could signal a new phase between two uneasy neighbors seen at risk of reigniting one of Africa's bloodiest wars.
"The two countries decided to step back from the brink. They looked at each other and said we are going in the wrong direction," Lyman told the Senate Foreign Relations Committee.
"We have seen these re-commitments before. So while we take a great deal of hope from them, a lot will depend on what happens over the next several weeks."
(Editing by Ross Colvin)