Wearing a suit in the yellow Lakers color, she began by singing her 2013 hit "XO" while a choir sang in the background and violinists played.
The song had a special meaning to Bryant, who died at 41 along with his daughter Gianna, 13, and seven others in a helicopter crash last month.
"I'm here because I love Kobe, and this was one of his favorite songs," she said.
When performing "XO," Beyoncé swapped out one of her lyrics — "Your heart is glowing/ And I'm crashing into you" — to instead say "laughing into you" in attempt to avoid insensitive language.
She then performed her song "Halo" as Bryant's widow, Vanessa, applauded in appreciation.
Beyoncé then tearfully saluted the sky in memory of Bryant before a video featuring his classic highlights from his legendary Lakers career was shown on the Jumbotron.
Two additional music superstars, Alicia Keys and Christina Aguilera, later took the stage during the memorial with respective performances in Bryant's honor.
Sitting down at a piano colored purple, another Lakers hue, Keys played Beethoven's "Moonlight Sonata." The classic is a favorite of Bryant and his wife.
"Vanessa, when you told me the Moonlight Sonata is such a beautiful part of your love story bc Kobe vowed to learn it for you, I was speechless," Keys wrote on Twitter following the memorial service. "I felt the depth of your love for each other & your girls with every note I played today. The love between u lights up the world."
Later in the program, Aguilera delivered a moving rendition of "Ave Maria" with an orchestra. The performer sang in Italian in tribute to the place Bryant spent his childhood and learned to play basketball.