Christian, who turned 9 years old in early June, had invited all his classmates to the party at his home in the city of Meridian, his mom, Lindsay Barrus Larsen, told ABC News.
But after days of no RSPVs, Larsen became worried.
She wondered if he ever passed the invites out, but soon learned that he did and only one girl told him that she would go.
"At that point, I was just so happy that the one girl had responded," she told ABC News on Wednesday. "I knew with one other girl we would just make a great day of it."
Yet it didn't stop her from wondering if the lack of responses was, in part, because Christian is autistic.
"The hardest thing, is I do understand. It can be uncomfortable to try to be a friend with someone who has had outbursts and cried in class," she wrote in a post detailing the event on Facebook. "It's hard when maybe you tried at the start of the year, and he kept wandering off in the middle of the game."
Yet as she was planning the party for Christian, his family and the one classmate, a friend reached out with an offer.
The friend said that her husband knew the coach of the Nampa High School football team who wanted to come to the party "with some of his best players."
After a bit of hesitation, Larsen accepted "because if [a] community wants to come together, and celebrate Christian, why should I stop that?"
She also thought it would be a good opportunity for others to get to interact with Christian and better understand his special needs.
"The more that you socialize and interact with people who are different, it doesn't matter what the difference is, but you become more accepting and you start caring about the world around you more," she said.
Christian was out playing in the backyard when the football team sneaked in through the front door and emerged on the patio.
"Christian! Christian! Christian!" they chanted amid cheers and claps.
Christian, with his jaw dropped, fell to the ground.
The team, appropriately, gifted him a football.
"Now we can play a real game," Christian said through a smile.
Larsen said the team stayed until the end of the party, playing with the kids and singing Happy Birthday.
"It was truly amazing to watch them…," she wrote on Facebook. "There is so much good in this world, and when things are hard, the good shines even brighter."