"Hello, Dolly!" won four, including best musical revival and best featured actor for Broadway veteran Gavin Creel.
"Oslo", a three-hour meditation on diplomacy, was named best play. She refused to be played off, silencing the orchestra as the crowd roared. "Dear Evan Hansen" finished with six out of its nine nominations, including best musical. The show centers on a profoundly lonely 17-year-old who fabricates a previous friendship with a classmate who has just committed suicide.
Platt thanked his cast mates, crew and family, calling his parents his heroes. "To all young people watching at home, don't waste any time trying to be like anybody else", he said, "because the things that make you unusual are the things that make you powerful".
Benj Pasek and Justin Paul, who recently won Oscars for the song "City of Stars" from the movie "La La Land", added to a remarkable year by earning Tonys for best score for writing the songs for "Dear Evan Hansen".
Best Performance by an Actress in a Featured Role in a Play: Cynthia Nixon, "Lillian Hellman's The Little Foxes".
Broadway enjoyed a record-breaking season this year thanks to last year's Tony victor and pop culture juggernaut "Hamilton", and musicals like "Sunset Boulevard", starring Glenn Close, and "Hello, Dolly!". Laurie Metcalf won her first Tony for best actress in A Doll's House, Part 2.
"Oslo", a crackling drama about the little-known backstory behind the 1993 Middle East peace talks, won the hard-fought competition for the best new play, reported New York Times.
"Am I dreaming? Is this some kind of insane dream?" she asked.
First-time Tonys host Kevin Spacey kicked off the show with a medley of songs referencing his self-doubt about successfully hosting the annual awards show compared to past hosts Neil Patrick Harris, James Corden or Hugh Jackman. How about: His impression of Bill Clinton even caught the fancy of a former vice president in the audience - Joe Biden. His Clinton joked about food and his wife's email problems, while his fictional one - accompanied by fictional wife Claire Underwood (Robin Wright) - admitted he wanted to leave before Midler started to thank anyone else.
The iconic EGOT honor is earned when any performer has won an Emmy, a GRAMMY, an Oscar and a Tony. Spacey, dressed as Close, sang "I'm coming out." and then paused, tantalizingly. "Your next host is found". Later, he and Patti LuPone closed the show with a lovely duet of "The Curtain Falls" by Bobby Darin, a role he played onscreen.
Best Revival of a Play: "August Wilson's Jitney". The show's writer, Steven Levenson, won for best book of a musical, and Alex Lacamoire earned one for best orchestrations (after winning past year for "Hamilton.") And Rachel Bay Jones won her first Tony - featured actress - for her heartbreaking portrayal of a mother who struggles to understand and help her son, Evan, as he gets caught in a bad lie that he can not control.