The boy – identified by police as "Josh" – ran out at the start of the parade after he noticed one of the Honor Guard members holding the American flag had his shoe untied.
Without any hesitation, Josh ran into the parade, kneeled down and made sure the loose laces wouldn't trip up the guard during the march.
Wendy Smith snapped the photo at the parade and shared it on Facebook, saying: “We need more of his type in the world.”
Arlington Police Chief Will Johnson also shared Smith’s photo of the moment on Twitter, praising Josh for his quick action.
“We should all be so kind. I have a Chief Challenge coin for you,” he wrote.
Twitter users were quick to send praise for Josh.
“Josh, young man, your parents should be so proud of you. Loved seeing what you did for the Arlington PD Honor Guard and the Chief of Police from Robinson, Tx,” one person wrote.
According to the police department, Josh is the grandson of Dennis Wiles, the pastor of First Baptist Church of Arlington.