Other guests appearing during the two-hour program included show creator Matt Groening, former "Simpsons" writer Conan O'Brien, comedian Jon Lovitz, pro skateboarder Tony Hawk and Oscar-winning composer Hans Zimmer.
Zimmer, wearing a jacket covered with Bart faces, performed the music he composed for the Oscar-nominated short film "The Longest Daycare," which shows how Maggie saves a butterfly from a classroom bully.
At least 60 members of the Gay Men's Chorus of Los Angeles filled the stage for a soaring rendition of "Spider Pig," the song Homer dedicated to his special pet pig in "The Simpsons Movie."
Then chorus members stripped off their robes to reveal sequined vests as they sang the Mr. Burns' song about wearing puppy fur, "See My Vest," which culminated with a Rockettes-style kick line.
Azaria embodied several of the "Simpsons" characters he brings to life with his voice, including Moe and Apu, Disco Stu, Professor Frink and Duff Man. While portraying the beer-boasting Duff Man, a group of women dressed as Duff cheerleaders came onstage and fired T-shirt cannons into the crowd.
Lovitz offered a tribute to the late Phil Hartman, a "Simpsons" regular who voiced various characters on the show until his death in 1998.
The entire Hollywood Bowl was Simpson-ified for the program, which continues on Saturday and Sunday night. Plastic doughnuts dangled above concertgoers' heads and life-sized cardboard cutouts of show characters were scattered throughout the venue.
New "Simpsons" animations were created just for the concert, including a peek at the Simpson family arriving at the Hollywood Bowl and Homer trying to resist pushing the "fireworks" button. Another bit showed Maggie launching the fireworks, and with that, pyrotechnics exploded above the famous Bowl shell.