Media playback is unsupported on your device Media caption Obama reminded at youth event: 'I'm old'

Former President Barack Obama embraced a warm homecoming at University of Chicago, where he stepped back into the public eye while hosting a youth forum on civic engagement.

"What's been going on while I've been gone?" he quipped as he entered the stage to an uproar of applause on Monday.

Fresh off a three-month hiatus that included sun-soaked beach holidays and news of a forthcoming memoir, the 44th president made his return with ease - and without a tie - despite the current dismantling of his legacy back in Washington.

But Mr Obama, a former constitutional law professor at University of Chicago (UofC), spent less time talking about his old job at the White House and instead focused on his next task at hand: passing the political baton to a new generation.

"The single most important thing I can do is help in any way to prepare the next generation of leadership to take up the baton and take their own crack at changing the world," he told an auditorium full of Chicago-area students and community organisers.

Media playback is unsupported on your device Media caption Obama warning to young people: 'Be careful with your selfies'

The former president appeared alongside a mix of young civic leaders including a local senior high school student, an Indian immigrant who lost a state representative race, a US Army veteran college student and a member of UofC's Young Republicans.

And though he took centre stage, Mr Obama used the next 80 minutes to press his featured speakers about their own leadership challenges, at times offering maxims from his own political career.

Image copyright Getty Images

Image copyright Reuters Image caption The former president went kite-surfing with Richard Branson after leaving office

"It felt very intimate," Sarah Evans, 19, told the BBC.

"Everything he was saying was very meaningful and specific to us."

Students huddled together outside the auditorium after the event, sharing notes on their favourite lines lifted from the former commander-in-chief.

Ms Evans, a Northwestern University student, recited Mr Obama's words on what he did during his time as a community organiser on Chicago's South Side.

"Listen to understand rather than listen to respond," he told the crowd, noting it was actually a lesson he learned in marriage. "That will save you a lot of heartache and grief."

Afreen Ahmed, a 19-year-old UofC student, was struck by Mr Obama's response when asked about his 2000 loss in a race for a US House of Representatives seat in Illinois.

Image copyright Getty Images Image caption Senator Obama campaigning in 2004

It was the "sole time" in his political career, Mr Obama revealed, that he ran because he thought it was the next move rather than what he really wanted to do.

"Worry less about what you want to be," he said, "and worry more about what you want to do".

That piece of advice was a reminder for why Ms Ahmed takes on leadership roles in school programmes like the UofC Institute of Politics' Leaders of Colour and within her Muslim community.

"You can get so caught up in the positions and the titles and your career and it becomes less about the work that you're doing," she said.

Mr Obama was quick to emphasise that civic engagement, however, was not just about running for elected office or showing up on election day.

Image copyright Getty Images Image caption Obama did not speak about the current White House administration

Though he evaded talking about his successor, Mr Obama lamented that the decline of civic organisations like union clubs and churches, where Americans could find common ground, had deepened the growing divisions across the US.

"We're a more individualistic society," he explained. "I think that has a spillover for civic engagement, but also empathy because we're dealing with fewer people."

But much like the farewell speech he delivered in Chicago three months earlier, Mr Obama left his audience with another note of optimism, calling on a new class to usher in change.

Image copyright Getty Images Image caption Obama has not yet spent much time yet in his post-White House home in Washington

"It's a message a lot of people need to hear right now," said Hanna Addis, 19.

"Things are hard now, especially with such a shift in the political climate, and we need to remember we are a generation open to having more dialogue with each other."

"Are there ways in which we can knock down some of the barriers that are discouraging young people about a life of service?" Mr Obama asked.

"And if there are, I want to work with them to knock down those barriers."

And once this next generation begins moving toward a path of leadership, he continued: "I think we're going to be just fine."