Portside

His was far from the only political statement of the evening: With the words “Don’t Trump America” written on his back, the singer Usher used his performance to make a statement against Donald J. Trump. And when Taraji P. Henson, the star of “Empire,” accepted her best actress award, she also warned the audience about Mr. Trump.

But it was Mr. Williams who provided the highlight of the night with a nearly five-minute speech, delivered after he accepted the year’s humanitarian award.

Since 2009, Mr. Williams has played the role of Dr. Jackson Avery on “Grey’s Anatomy.” When he is not working on the set of the hospital drama, Mr. Williams, a former teacher, champions causes related to civil rights. He starred in and produced “Stay Woke: The Black Lives Matter Movement,” a documentary that premiered last month on BET. He produces Question Bridge, an art project about the experience of black men in America, and works with Sankofa, an organization dedicated to ending racial injustice. Mr. Williams is also on the board of the Advancement Project, a national civil rights organization.

The child of a white mother and a black father, Mr. Williams told The Guardian last October that his parents had shaped his activist roots, and said that being biracial allowed him to see both sides of a cultural divide.

“I have access to rooms and information,” he told the newspaper. “I am white and I am also black. I am invisible man in a lot of these scenarios. I know how white people talk about black people. I know how black people talk about white folks.”

But on Sunday, he delivered a speech that spoke solely to black Americans, and drew thunderous applause and shouts from the audience. Mr. Williams addressed the deaths of Tamir Rice, Eric Garner, Sandra Bland and Rekia Boyd, all black people who died during confrontations with the police.

“‘You’re free,’ they keep telling us,” he said. “‘But she would’ve been alive if she hadn’t acted so … free.’”

He ended his speech by calling for an end to racial oppression and cultural appropriation, including a reference to the Billie Holiday song, “Strange Fruit,” a meditation on racism and lynchings.

“Ghettoizing and demeaning our creations then stealing them, gentrifying our genius and then trying us on like costumes before discarding our bodies like rinds of strange fruit,” he said. “The thing is, though, the thing is that just because we’re magic, doesn’t mean we’re not real.”

Read His Speech in Full:

“This award, this is not for me. This is for the real organizers all over the country. The activists, the civil rights attorneys, the struggling parents, the families, the teachers, the students, that are realizing that a system built to divide and impoverish and destroy us cannot stand if we do.

All right? It’s kind of basic mathematics:, the more we learn about who we are and how we got here, the more we will mobilize. Now this is also in particular for the black women, in particular, who have spent their lifetimes dedicated to nurturing everyone before themselves. We can and will do better for you.

Now, what we’ve been doing is looking at the data and we know that police somehow manage to de-escalate, disarm and not kill white people every day. So what’s going to happen is we are going to have equal rights and justice in our own country or we will restructure their function and ours.

Now — I’ve got more, y’all. Yesterday would’ve been young Tamir Rice’s 14th birthday, so I don’t want to hear anymore about how far we’ve come when paid public servants can pull a drive-by on a 12-year-old playing alone in a park in broad daylight, killing him on television and then going home to make a sandwich. Tell Rekia Boyd how it’s so much better to live in 2012 than 1612 or 1712. Tell that to Eric Garner. Tell that to Sandra Bland. Tell that to Darrien Hunt.

Now the thing is though, all of us in here getting money, that alone isn’t going to stop this. All right? Now dedicating our lives to get money just to give it right back for someone’s brand on our body, when we spent centuries praying with brands on our bodies and now we pray to get paid for brands on our bodies.

There has been no war that we have not fought and died on the front lines of. There has been no job we haven’t done, there’s been no tax they haven’t levied against us, and we’ve paid all of them. But freedom is somehow always conditional here. “You’re free,” they keep telling us. But she would’ve been alive if she hadn’t acted so… “free.”

Now, freedom is always coming in the hereafter. But, you know what though? The hereafter is a hustle. We want it now. And let’s get a couple of things straight, just a little side note: The burden of the brutalized is not to comfort the bystander. That’s not our job, all right, stop with all that. If you have a critique for the resistance, for our resistance, then you better have an established record of critique of our oppression. If you have no interest in equal rights for black people then do not make suggestions to those who do. Sit down.

We’ve been floating this country on credit for centuries, yo, and we’re done watching and waiting while this invention called whiteness uses and abuses us, burying black people out of sight and out of mind, while extracting our culture, our dollars, our entertainment like oil, black gold. Ghettoizing and demeaning our creations then stealing them, gentrifying our genius and then trying us on like costumes before discarding our bodies like rinds of strange fruit. The thing is, though, the thing is that just because we’re magic, doesn’t mean we’re not real.”

A version of this article appears in print on June 28, 2016, on page C3 of the New York edition with the headline: How a Cri de Coeur on Racial Injustice Stole the Scene at the BET Awards.