The 34-year-old duke of Sussex mentioned Archie, his 2-month-old baby boy with wife Meghan Markle, and Diana, who died at age 36 in August 1997, at the Diana Award National Youth Mentoring Summit Tuesday.
"I'm struck by a few things today, most of which is the power of the invisible role model," Harry said, according to E! News. "The person who may be sitting here today that doesn't realize that someone looks up to them, that -- for that person -- you inspire them to be kinder, better, greater, more successful, more impactful."
"Perhaps it's the newfound clarity I have as a father knowing that my son will always be watching what I do, mimicking my behavior, one day maybe even following in my footsteps. But it's not just my role as a father that shows me that; it's in the people I see every day that don't realize how inspirational they are to those watching."
Harry said Diana exemplified the traits of a good role model without realizing the impact she had on people around the world.
"My mother, Princess Diana, was a role model to so many, without realizing the impact she would have on so many lives," he said, according to People. "You don't have to be a princess or public figure to be a role model, in fact it's equally valuable if you're not because it's more relatable."
Harry ended his speech by mentioning Diana's birthday. Diana would have turned 58 years old Monday.
"To the mentees here today, I am incredibly proud of what you've achieved, and I can safely say that my mother, who would have turned 58 yesterday, would feel the same," Harry said.
The summit was hosted by the Diana Award, the only official charity in Diana's name. The organization uses mentoring as a way to help young people develop the practical skills they need to achieve their goals.
Harry and Markle welcomed Archie in May. The couple will have their son christened at a private ceremony Saturday at the Queen's private chapel at Windsor Castle.