"The only wrong thing to say, is to say nothing," Markle said Wednesday evening during the virtual graduation ceremony at the all-girls Immaculate Heart High School, in Los Angeles. "Because George Floyd's life mattered."
Prince Harry's wife, whose mother is black, listed the names of black people who had been killed in the United States, acknowledging there were many more who were unnamed.
Markle apologized to the 2020 class for having to experience what should be a "history lesson" as a "reality."
The Duchess of Sussex recounted how in 1992, during riots that broke out after the police beating of Rodney King, she "rushed home" during curfew, and saw armed men, smelled smoke and found the tree in front of her house "completely charred."
A "senseless act of racism" had provoked those events too, she said.
"I'm so sorry that you have to grow up in a world where this is still present," added Markle, who moved back to California earlier this year, a few months after the royal couple announced that they would "step back" from their duties in the British royal family, less than two years after their wedding in 2018.
The image of a biracial, foreign woman welcomed into the bosom of white, traditionalist Britain carried colossal symbolism — and even a hope that it signaled greater inclusivity and tolerance.
But since their wedding, the couple have repeatedly complained of toxic coverage in the British media, which some of their supporters say has veered into racist harassment and bullying.
Urging the students to use their voices and compassion to rebuild broken social foundations, Markle said: "We are seeing people stand in solidarity, we are seeing communities come together and to uplift.
"I know you know black lives matter ... we need you," she said. "I'm cheering you on."
Protests have swept dozens of U.S. cities since Floyd, 46, died after police officer Derek Chauvin, who is white, kneeled on his neck for more than eight minutes in Minneapolis, Minnesota. On Wednesday, three more former police officers were charged in connection with his death — five days after charges were brought against Chauvin.
The three, Tou Thao, Thomas Lane and J. Alexander Kueng, were charged with aiding and abetting murder. The murder charge against Chauvin was also elevated to second-degree, from third-degree. The four men were fired on May 26.
The protests have also taken a global turn. In London, thousands of demonstrators met near Buckingham Palace on Wednesday chanting "justice now," and holding placards reading "we can’t breathe" — final words uttered by Floyd before he died.