Bono and Stevie Wonder at Global Citizen Festival
Bono and Stevie Wonder at the Global Citizen Festival. Getty Images

An impassioned speech on guns by Wonder and slick sets by Alicia Keys, John Mayer and Kings of Leon highlight a day of doing right in Central Park

Stevie Wonder made believers out of a youthful crowd of 60,000-plus at the Global Citizen Festival, held Saturday in New York City's Central Park, with a joyful display of iconic soul-funk hits, a smattering of famous cameos and an awareness on his part that this night was about much more than great music.

U2 frontman Bono, in his second appearance of the day, channeled a boxing announcer to introduce Wonder, the headliner of a headliner-filled lineup that included Kings of Leon, Alicia Keys and John Mayer. "The true disciple of Sir Duke," Bono said of Wonder, "He raises our hopes when he raises his voice! There is only one!"

Wonder and his outsized band went to work playing a generous sampling of his most crowd-pleasing tracks, including "Higher Ground," "Living for the City," "I Just Called to Say I Love You," "Superstitious" and "My Cherie Amour," with the Motown legend alternating between piano, keyboard and for one glorious moment, a keytar. Saturday happened to be the 37th anniversary of his signature album, "Songs in the Key of Life," a bit of trivia that probably had nothing to do with him performing "Sir Duke" and "Isn't She Lovely" (he started "I Wish" at one point but quickly decided against it). 

Even at 63, Wonder's voice remains a powerful instrument, capable of both acrobatics and nuance that will surely perplex generations to come. Late in his set, Wonder brought out two of those followers, R&B auteurs Janelle Monae and Maxwell, who just came out and said it: "I can't believe this is happening!" while singing an improvised song with the legend.

Now in its second year, the Global Citizen Festival is a free ticketed event spearheaded by the Global Poverty Project, an advocacy group that works to end extreme poverty by 2030. Fans gained access by volunteering or helping to spread the word about the various programs. Wonder, a United Nations Messenger of Peace since 2009, embraced the moment. "We will end extreme poverty in our lifetime," he said. "Together we can work it out, and we will reach our higher ground."

He also seized on another issue, gun violence, and wrapped it with his most emotional performance of the night, a version of John Lennon's "Imagine." "Every time I do this song it brings such emotion to my heart," he said of Lennon, noting that he was killed just a short walk from the Great Lawn. "Most of all to know that we lost this man because of a gun. Because we don't have laws dealing strong enough with mental illness, we lost a great man."

In contrast with Wonder, his immediate opener, John Mayer, didn't do much talking throughout his polished set of festival groove rock. While his stronger-than-ever voice seems to have made a miraculous recovery following vocal cord surgery, the star of the show was his guitar work during songs like "Waiting on the World to Change," the traditional "Goin' Down the Road Feelin' Bad" (though he specifically cited the Grateful Dead version) and the bluesy "Gravity."

Earlier, Alicia Keys performed for her hometown crowd, powering through an energetic set that included "New Day," "You Don't Know My Name," "Fallin'," complete with a prog-R&B breakdown, and a rocking jam of "Girl on Fire," which gave her a chance to bring up one of the night's signature topics: gender equality. "We're all on fire up in here," she said. "If you empower women, we're gonna change the world!"

The day also saw appearances by celebrities including Olivia Wilde, Soledad O'Brien and Will.i.am, who announced a partnership between Global Citizen and his EKOCYCLE brand while wearing clothing made in part with plastic bottles. World leaders in attendance included Malawi President Joyce Banda, Crown Princess Mary of Denmark, U.N. Secretary-General Ban Ki-moon and Liberian President Ellen Johnson Sirleafe, who was introduced by Bono ("A heroine for all kinds of reasons," he called her). Elvis Costello provided some set-changing music with a mashup of new song "Tripwire" and the classic "(What's So Funny 'Bout) Peace, Love, and Understanding."

The day began with a band accustomed to headlining -- not opening -- festivals, Kings of Leon, who are only days removed from releasing their sixth studio album "Mechanical Bull." The early set inevitably meant some fans who were stuck in line (see tweet) missed out on the only rock band of the day (in contrast last year's festival was almost exclusively rock).

For those who made it in time, KoL played one of the most energetic sets of the day, lacing into recent single "Supersoaker," as well as "Be Somebody," "Notion" and their biggest arena-fillers "Sex on Fire" and "Use Somebody." 

At last year's event there were three major acts (Neil Young, Foo Fighters, Black Keys) and two openers (K'Naan and Band of Horses). This time organizers reduced the tally to four major artists, which Global Poverty Project co-founder and CEO Hugh Evans told Billboard was a "deliberate choice" on their part. "We wanted them to have the opportunity to get on stage and really get into it. The bands value it."

Evans stressed that "it's not just about a concert, it's about a true movement" and thanked the "whole music industry for helping us turn this into a 365 day movement. That's our commitment. We want this to grow. By the end of next year, we want to have over a million global citizens lined up. And that's where we want to take it.

"And we want those global citizens to call on Barack Obama, to call on David Cameron, to call on the new PM of Australia Tony Abbott to do what it takes for the poor and the vulnerable," he said. "And that's what makes this festival different, because the people don't just pay a $100 and go home. They've been working to get their tickets for months."