Prior to the contest, Leonard explained his decision to Tim Reynolds of The Associated Press, referencing his brother who served two tours of duty in Afghanistan with the Marines, as well as friends who are Navy SEALS.
"I absolutely believe Black lives matter," the 28-year-old said. He added: "Some of the conversations I've had over the past three days, quite literally, have been the most difficult. I am with the Black Lives Matter movement and I love and support the military and my brother and the people who have fought to defend our rights in this country."
Like San Antonio Spurs head coach Gregg Popovich - who also opted to stand for the anthem Friday - Leonard wore a "Black Lives Matter" shirt.
"I am a compassionate human being and I truly love all people," Leonard said. "I can't fully comprehend how our world, literally and figuratively, has turned into black-and-white. There's a line in the sand, so to speak: 'If you're not kneeling, you're not with us.' And that's not true.
"I will continue to use my platform, my voice, and my actions to show how much I care about the African American culture and for everyone. I live my life to serve and impact others in a positive way."