Kai Trump, the teenage granddaughter of former US president Donald Trump granddaughter, debuted at the Republican National Convention yesterday to applause and cheers to share a side of her grandfather "that people don't often see".

The 17-year-old was introduced by her father, Donald Trump Jr who said Kai called him on Monday to say she wanted to speak at the RNC.

Telling stories that appeared to portray a softer image about Mr Trump, his eldest granddaughter described him as "just a normal grandpa" who gave them "candy and soda when our parents aren't looking".

"He always wants to know how we're doing in school," she said. "When I made the high honour roll, he printed it out to show his friends how proud he was on me."

The crowd went silent when she recalled hearing about the shooting of her grandfather on Saturday.

"I was shocked when I heard that he has been shot, and I just want to know if he was okay," she said.

"It was heartbreaking that someone would do that to another person."