LOS ANGELES

Filmmaker Spike Lee won his first competitive Oscar Sunday night at the 91st Annual Academy Awards that was awash in historic wins for diversity, including awards for Ryan Coogler’s superhero sensation “Black Panther,” Alfonso Cuaron’s black-and-white personal epic “Roma” and the Freddie Mercury biopic “Bohemian Rhapsody.”

“Green Book,” the hotly debated road trip drama based on the travels of pianist Don Shirley, played by Mahershala Ali, to the Deep South with his white chauffer, former bouncer Tony “Lip” Vallelonga, played by Viggo Mortensen, stunned many in the Dolby Theatre audience and those watching at home when it won the Academy Award for best picture.

Mr. Lee’s win for best adapted screenplay for his drama “BlacKkKlansman,” about a black undercover cop in Colorado exposing a white supremacists ring, gave the Dolby Theatre ceremony its signature moment. As the crowd rose in a standing ovation, Mr. Lee leaped into the arms of presenter Samuel L. Jackson. Even the backstage press room burst into applause.

In his acceptance speech, Mr. Lee, whose film included footage of President Trump following the violent white supremacist protests in Charlottesville, spoke about the upcoming election.

“The 2020 election is around the corner. Let’s all mobilize. Let’s be on the right side of history,” said Mr. Lee, who was given an honorary Oscar in 2015. “Let’s do the right thing! You knew I had to get that in there,” he said, referencing the name of his 1989 classic film.

Ruth E. Carter, a Hampton University graduate who got her start working with Mr. Lee on the 1998 film, “School Daze,” won the Oscar for costume design for “Black Panther,” while Hannah Beachler won for its production design. It was a first win for African-Americans in both categories.

Ms. Beachler broke down in tears during her acceptance speech with fellow production design awardee Jay R. Hart, saying she “stands here stronger than … yesterday.”

She helped create the cinematic world of Wakanda, the fictional homeland of the main character, played by actor Chadwick Boseman.

Ms. Carter and Ms. Beachler also became just the second and third African-American women to win non-acting Oscars.

“It just means that we’ve opened the door,” Ms. Carter, a veteran costume designer, said backstage. “Finally, the door is wide open. I’m mentoring in hopes of raising others up and give them hope.”

Ms. Carter, who garnered previous Academy Award nominations for her work on “Amistad” and “Malcolm X,” dedicated her award to her 97-year-old mother.

“Marvel may have created the first black superhero,” Ms. Carter said during her acceptance speech. “But through costume design, we turned him into an African king.”

Ms. Carter has said she drew inspiration for the film’s stylish and colorful garments from her travels to Africa. She spoke with people of the continent to understand the history of each artifact to ensure the different characteristics were represented properly in the film.

The costumes have become so popular that people of different ages and ethnicities have worn Black Panther-themed costumes to theaters and at parties. Some even dressed in Wakanda couture at a pre-Oscar event.

The lush, big-budget “Black Panther” also won an Oscar for Ludwig Goransson’s score.

In the hostless event, the motion picture academy leaned on its presenters to engage the audience. Tina Fey, alongside Amy Poehler and Maya Rudolph, welcomed the audience to “the one-millionth Academy Awards.”

Ms. Rudolph summarized a rocky Oscar preamble that featured numerous missteps and backtracks by the Academy of Motion Picture Arts and Sciences: “There is no host, there won’t be a popular movie category and Mexico is not paying for the wall.”

The trio then presented best supporting actress to Regina King for her role as a matriarch in Barry Jenkins’ adaptation of James Baldwin’s “If Beale Street Could Talk.” The crowd gave Ms. King a standing ovation for her first Oscar.

“To be standing here representing one of the greatest artist of our time, James Baldwin, is a little surreal,” said Ms. King, who also thanked her mother who was seated in the audience. “James Baldwin birthed this baby.”

Two years after winning for his role in “Moonlight,” Mahershala Ali won again for his supporting performance in the road trip drama “Green Book,” a role many said was really a lead.

Mr. Ali is the second African-American actor to win two Oscars following Denzel Washington, who won for “Glory” and “Training Day.” Mr. Ali dedicated the award to his grandmother.

“Green Book” also won for best original screenplay.

“Bohemian Rhapsody,” which kicked off the ABC telecast with a performance by Queen, won four awards despite pans from many critics and sexual assault allegations against its director, Bryan Singer, who was fired in mid-production.

The film’s star, Rami Malek, won best actor for his full-bodied and prosthetic teeth-aided performance, and the film was honored for editing, sound mixing and sound editing.

“We made a film about a gay man, an immigrant who lived his life unapologetically himself,” Mr. Malek said in accepting his award. “We’re longing for stories like this. I am the son of immigrants from Egypt. I’m a first-generation American, and part of my story is being written right now.”

The film “Roma,” notched Mexico’s first foreign language film Oscar. Mr. Cuaron also won best cinematography, becoming the first director to ever win for serving as his own director of photography. Mr. Cuaron referenced an especially international crop of nominees.

“When asked about the New Wave, Claude Chabrol said there are no waves, there is only the ocean,” Mr. Cuaron told the audience, referring to the French filmmaker. “The nominees tonight have proven that we are a part of the same ocean.”

The inclusivity of the winners Sunday stood in stark contrast to the #OscarsSoWhite backlash that marked the 2016 and 2015 Academy Awards. Since then, the academy has worked to diversify its largely white and male membership, adding several thousand new members and opening the academy internationally.