Brayden Harrington sat in his home, speaking to a mobile phone camera and reading carefully from a piece of paper.
He looked up and told the world how the former vice president, by speaking about his own experience, had helped him overcome a difficult challenge.
“We stutter,” Brayden said in a video that aired shortly before Mr Biden accepted his party’s presidential nomination on the final night of the Democratic National Convention.
Joe Biden made me feel more confident about something that's bothered me my whole life. Joe Biden cared. Imagine what he could do for all of us
The teenager, from Concord, New Hampshire, got stuck briefly on the “s” sound and bravely worked his way through the word.
His face showed strain but also determination to force out the sound.
“It’s really amazing to hear that someone became vice president” despite stuttering, Brayden said.
“He told me about a book of poems by Yeats that he would read out loud to practice.”
Mr Biden has spoken frequently about how overcoming a stutter was one of the hardest things he has done in life.
Brayden and Mr Biden met at a CNN town hall event in Concord in February, where the politician spoke about overcoming a severe childhood stutter.
He has talked frequently publicly through the years about the anger and frustration of being mocked by classmates and a nun in Catholic school – and how that motivated him to work to overcome it.
“It has nothing to do with your intellectual makeup,” he said at the town hall.
After the event, Mr Biden invited Brayden backstage to talk more about learning to control a stutter.
Mr Biden noted that he had practised by speaking as he looked at himself in the mirror.
He also gave the boy a speech he had prepared for delivery, complete with markings he had made on its pages that showed where he had time to take breaks and pauses so that the words would come out more smoothly.
Brayden held up that speech for convention viewers.
“I’m just trying to be a kid,” Brayden said.
“And in a short amount of time, Joe Biden made me feel more confident about something that’s bothered me my whole life. Joe Biden cared. Imagine what he could do for all of us.”
He added: “Kids like me are counting on you to elect someone we can all look up to.”
Mr Biden has talked about his stutter frequently on the presidential campaign trail and how it sometimes returns on certain words, especially if he is tired.
After he talked about it during a Democratic primary debate in December – and even started to make the sounds of a stutter – then-White House press secretary Sarah Sanders ridiculed Mr Biden on Twitter.
The tweet was later deleted and Ms Sanders apologised.
Mr Biden said afterwards that he had no regrets “because I know what it’s like to be humiliated”.
