Chance the Rapper didn't headline Fake Shore Drive's Red Bull Sound Select showcase at South by Southwest last month—in fact he was only second on the bill, performing after fellow Chicago MC Show­YouSuck. But you could be forgiven for assuming that everybody was there to see him: when he was done, a big chunk of the audience left, and the crowd didn't get that big again till just before the Cool Kids played, three acts later.

Chance, aka Chancelor Bennett, turned 20 this month, and his youthful energy gives him a magnetic charisma onstage. Most rappers don't do much more than pace around, maybe bobbing or jumping at particularly dramatic moments, but Chance keeps up constant frenetic motion—at SXSW he flailed his arms like a push puppet, kicked the air, stomped up and down, threw milk cartons of water into the audience, and busted out a busy, shuffling dance somewhere between footwork and the Charleston. He's playful and down-to-earth, like a goofy kid next door, and when he switches from rapping to singing his nasal voice becomes oddly sweet.

Just moments after Bennett bounded onstage in Austin, a couple fans up front started screaming for "Juice," a song he'd released in late January. He worked the crowd nonstop, teaching them how to sing the song's one-word chorus and leading chants of "Sosa free" to celebrate Chief Keef's release from prison that day.

"Juice" is one of four tunes Bennett has released so far from his second mixtape, Acid Rap, which drops Tue 4/30 (the others are "Good Ass Intro," "Acid Rain," and "NaNa"). He's been promoting Acid Rap for months—his efforts began in earnest with a headlining gig at Metro in November—and plenty of folks at the Fake Shore Drive showcase clearly knew the new material already. "People were just so invested in his set," says Fake Shore founder Andrew Barber. "I was walking around to the VIP area, where usually people aren't paying any attention—they're talking, they're drinking—and everybody's like, 'Who's this kid?'"

Bennett has been performing publicly as "Chance" or "Chance the Rapper" only since July 2011—he's part of the Save Money crew, which also includes popular group Kids These Days—and aside from Acid Rap his sole album-length release is the mixtape #10Day, which came out in April 2012. But he's built a local audience quickly: a couple months after #10Day, which was inspired by his ten-day suspension from high school for smoking weed off-campus, he sold out Lincoln Hall. Bennett is an enthusiastic self-promoter, eager to connect with his audience—he visits high schools to sell concert tickets, sign posters, and have his picture taken with fans. He's also had a lot of opportunities to perfect his live show since #10Day came out—last summer he filled in for Danny Brown as the opener on a Childish Gambino tour.

People outside Chicago are starting to catch on in a big way. In January XXL magazine put Bennett on the fan ballot for its 2013 "Freshman Class" issue, which recognizes the top tier of up-and-coming rappers. He didn't make it in (honorees included Schoolboy Q, Chief Keef, Joey Bada$$, Action Bronson, and Angel Haze), but by the time the issue was published, other national outlets had started paying attention to Bennett—most notably Pitchfork, which reviewed "Juice."

The video for "Juice" is a great introduction to Bennett: filmed on a late night in January in Times Square by Save Money videographer Austin Vesely, it captures his fluid, startling onstage dance style from up close. "Chance got to be Chance as a performer," says Vesely. And the relatively new video for "NaNa," which costars comedian Hannibal Buress, shows off Bennett's silly sense of humor: he spends a good percentage of the clip wearing a chicken suit, at one point getting down with Spider-Man, Venom, and Wolverine.

Raised in Chatham, Bennett is a natural-born performer—at least according to his dad, Ken Williams-Bennett, who works for the federal government as a regional representative to the U.S. Secretary of Labor. "I remember his graduation from preschool," Williams-Bennett says. "He did a skit where he was Michael Jackson, with a little leather jacket on, a glove, and sunglasses."

Bennett's tastes soon evolved to take in a lot more than the King of Pop. "I've been wanting to rap since I was eight years old," he says. When Kanye West released The College Dropout in 2004, shortly before Bennett's 11th birthday, he was hooked for good. Thanks to an older cousin, a rapper who goes by Chef Sean, he entered a studio for the first time in seventh grade. In eighth grade Bennett started a rap group called Instrumentality (who recorded a song that would eventually appear on #10Day, "Nostalgia") and got involved in slam and performance poetry. While in high school at Jones College Prep, he was a regular at the Harold Washington Library's YouMedia center and attended and participated in events put on by Young Chicago Authors, including its Tuesday-night #WordPlay open mikes and its renowned monthlong Louder Than a Bomb festival.

"Chance was fortunate to be immersed in a community of young writers—both at Louder Than a Bomb and Young Chicago Authors and at YouMedia. But the larger culture of hip-hop poetry and spoken word that we've been building over 15 years in Chicago, Chance was in some ways born into that," says poet and YCA artistic director Kevin Coval, who founded Louder Than a Bomb. "The way he pulls apart language, the way he stretches words in song, that's I think a part of a moment and a movement in Chicago."

Coval describes Bennett as open to new experiences and willing to try to connect with any audience, whether in a CPS school or out in the suburbs. Bennett's father says his son cares about his neighbors, and remembers him looking after an elderly woman who lived nearby. "Community has always been important to me and Chance. Even when he was a little guy, he went out to do community projects," Williams-Bennett says. "I think Chance understands that we've gotta watch out for each other and he's very respectful when it comes to that kind of stuff."

"I think she used to watch my dad when he was a kid," says Bennett. "She was friends with my dad's grandmother, 'cause my dad stayed in the crib that I live in now when he was a kid. It's just been the same old lady living there I guess his whole life and then my whole life."

When he was 15, Bennett also spent a year acting as a sort of surrogate dad to his younger brother, Taylor, who's three years younger and also an aspiring rapper. Their father, who'd started his career in government as an aide to Harold Washington in the 80s and worked for Obama when the president was a U.S. senator, moved to D.C. for a year without the rest of the family after the 2008 election. "It was kind of tight [financially]," Williams-Bennett says. "Chance did a wonderful job, and he watched out for his little brother and his mom."

Williams-Bennett is close with both his sons, but Bennett's decision to pursue music instead of a degree caused some friction. "I thought I was gonna run him for mayor or governor someday," he says. "When I tried to push Chance to go right into college, Chance pushed right back—this is what he wanted to do." When Bennett told his dad that he wanted to concentrate on hip-hop after he graduated from high school in summer 2011, it opened up a rift—the two didn't speak to each other for months. "I remember I used to be saying, like, 'I'm gonna be famous one day,'" says Bennett. "I remember saying that when I was in fuckin' fourth grade. My dad used to just hate that shit."

During his estrangement from his father, Bennett began playing out, testing material that would end up on #10Day. He caught the ear of Closed Sessions cofounder and former Ruby Hornet editor Alex Fruchter with his very first show as Chance. "I didn't know the back history; I just felt the energy," says Fruchter. "Immediately there was something that was relatable to the younger kids and older people."

By fall 2011, though, Bennett began to question his resolve—he even enrolled at Harold Washington College, though he only lasted a week. What refocused him on music was a homicide: in September he saw close friend Rodney Kyles Jr., a 19-year-old philosophy student at Roosevelt who rapped as In Rod We Lust, stabbed to death in a fight in Lincoln Park. "It was a really big thing because I was there and I saw it and I was really affected by it on a very personal level," Bennett says. He still grapples with Kyles's death, sometimes openly. On "Juice" he raps, "I ain't really been myself since Rod passed," and on "Acid Rain" he goes deeper: "My big homie died young, just turned older than him / I seen it happen, I seen it happen, I see it always / He still be screaming, I see his demons in empty hallways."

When Kyles died, Bennett hadn't spoken to his father for about three months, but that night he called his dad to get a ride home from Advocate Illinois Masonic Medical Center. "When I picked Chance up, he still had Rod's blood on his shirt," Williams-Bennett says. "I could've not been bringing my son home. The thought of not just not bringing my son home, but not being on the right page with him—I thank God every day for another opportunity." At that point Williams-Bennett made his peace with his son's ambitions as a rapper—he told Bennett he had a year to make something happen.

"Right after that I started being in the studio every day," Bennett says. "Didn't really go out anymore, stopped doing all the drugs I used to do—it changed my whole life around. It was a very sobering event." His father noticed too: "His performances were entirely different," Williams-Bennett says. "He understood his mortality."

Bennett also got support from his family and the scene. L-Boogie of ThemPeople let him use his studio for free over the next several months to make #10Day. His father helped him set up his first official solo event, a #10Day listening session at streetwear shop Leaders 1354 in November 2011 that drew such a big crowd it had to expand into two sessions to fit everybody. Coval invited him to hop onto bills at YCA in-school events, which paid a little and helped Bennett afford food and public transit. "I was eating like once a day, and sometimes less than that," Bennett says.

A whole bunch of folks worked with Bennett on #10Day, whether by producing or rapping or playing an instrument, and their names helped his debut get noticed: they include Save Money crewmates (Caleb James, Vic Mensa, Nico Segal) and Chicago scene stars (Chuck Inglish of the Cool Kids, Sulaiman of Treated Crew, the Blended Babies). He also developed a regular live band of sorts, with producer Stefan Ponce DJing, jazz and neosoul vocalist Lili K. singing, and Peter Cottontale playing keyboards; they still join him onstage whenever they can. And in spring 2012 Bennett acquired a full-time manager when DePaul student Patrick Corcoran dropped out of school to work for him. "If we were going to do it, we should do it right," Corcoran says.

They've obviously done it right—Corcoran says that cops had to shoo them out of the parking lot on a recent visit to Oak Park and River Forest High School because "there were 600 or 700 kids running out on the streets." Much of Acid Rap will remain under wraps till it drops—Bennett is still tinkering with it, and he hasn't publicized a track list or a list of featured rappers—but the songs that he has released show him at the top of his game. "Good Ass Intro," for example, melds a sample of Kanye's "Intro (I'm Good)" with a juke beat, and Bennett shouts out King Louie's "Money Dance" while rapping so fast it sometimes sounds like he's trying to cram in all the syllables he can before he needs to inhale. What little of Acid Rap that people have heard has been enough to convince many of them of something that Bennett's friends have long believed—that he's going to be a superstar.

"By the time SXSW hit, everybody was calling him up," Barber says. "Every brand wanted to work with him, every booker wanted to book him for a show, and every A&R or label VP was calling, trying to get a meeting with him . . . . It was crazy. I haven't ever seen anything like it."