Green, Boston's 26-year-old rookie, drew noticeable cheers inside Washington's Verizon Center with a first-quarter bucket thanks to the gaggle of college friends that made the long pilgrimage to cheer him on.
"When I got back [to Boston] and I talked to Kemba, he was watching the game on TV, when I scored that layup, he was like, ‘You had the whole city out, right?'" said Green. "I was like, ‘How did you know? You weren't even there.' He said, ‘Yeah, I heard it when you scored. It was very loud.'"
Green's traveling support system included an entire section of supporters with ties to Radford University, which he attended in neighboring Virginia. But it's a 250-mile and four-hour-on-a-good-day drive through the Shenandoah Valley. Another batch of family members made the drive up from Green's native Petersburg, Virginia and rented out two luxury boxes to cheer for him.
"I definitely heard the cheers," said teammate Marcus Smart. "He deserves it. He's been working hard and his opportunity is finally here an he's making the most of it."
Considering Green spent his first three years of professional ball playing in Spain, Italy, and Germany, his supporters are thrilled that it's just a car ride to see him now.
Family members rented a 12-passenger van for the more-than-four-hour trek to Philadelphia to watch Boston's opening night game against the Sixers. And Green was inactive for that game. They've made two similar treks to Charlotte to watch him as well.
Green beams with pride detailing what it means for him to play in front of his family again. Part of what pushed him to chase a spot on Boston's 15-man roster was the opportunity to be closer to young daughters, Khloe, 7, and Kylie, 1.
Some family members made a trip to Germany last year to spend Christmas with Green. But now he can look up at TD Garden and see them carrying around oversized cardboard cutouts of his head as they cheer him on during a random midweek matchup in January.
"Honestly, that was the ultimate goal for me, getting to be closer to my daughters," said Green.
Last week, the deadline for contracts to become fully guaranteed passed quietly, ensuring Green will collect all of his $898,310 rookie deal. It was never really in doubt given the potential Green has displayed, and yet he admits he was able to exhale a bit.
"Of course you were thinking about it," said Green. "At the same time, I can't let that cloud my vision. To get there, and to get past the deadline, it was a relief, even though I wasn't worried about it as much, but still - you never know with a business."
Green admits he still has some pinch-me moments in his rookie campaign.
"When I first got the offer from [Danny Ainge], it was a dream come true," said Green. "I still don't think it's really hit me. But every day, a random day, I can just be going to the grocery store, and I'm like, ‘Yo, I'm really in the NBA.'
"But I just can't look at it that way. It's a job. And I still got a long way to go."
Green is averaging 2.9 points and 1.5 rebounds over 7.8 minutes per game in 30 appearances. While his playing time typically only comes in bite-sized chunks, he's wowed Celtics fans with his freakish athleticism and has already amassed a mixtape of loud in-game dunks.
It's enough to make some wonder if he should be in the NBA's dunk contest. But, truth be told, dunk contests aren't really his thing.
"I feel like I overthink it," said Green. "In a game, it's like instincts. There's not much to think about."
While playing in Germany last year, Green got invited to participate in the dunk contest at the league's All-Star weekend. He misfired repeatedly on a 360 windmill dunk that he typically makes with ease and got booted in the first round of competition.
"I did horrible. I got knocked out first round. I actually came in last place I think," said Green. "Right now I'm still kinda scarred from it. It wasn't like a crazy dunk. It was just a dunk that I've done like 100 times. I just couldn't put it down. I don't know."
It's one thing to just explode to the basket in a game; it's another to have everyone's eyes on you waiting for a 'Wow' moment.
"It's a lot of pressure but, at the same time, I could have easily won it. Then I went between the legs and, how they did it over there, it's like, you dunk then your opponent dunks, then they vote who they want. I went between the legs and nobody voted for me so I was like, ‘Wow, I thought that was pretty sweet.'"
If the NBA did invite him, Green admits he'd have to give it a lot of thought.
For now, he's just focused on getting better and helping his teammates. He's marveled at how down to Earth everyone in the Celtics organization is and he's made himself at home. Like dumping water over Jayson Tatum's head during his postgame interview following Tatum's 41-point night last week.
And the veterans are looking out for him as well.
"A lot of the stuff we do, traveling and things like that, it's his first time doing it," said Smart. "He says it all the time, how blessed he is and how thankful he is to have the opportunity to be with us and be part of the crew. The dude is unbelievable. He's a freak of nature, athletically-wise. We've seen it. Good guy to be around, good teammate, just his all-around energy - it's contagious and rubs off on us in a good way."
Don't miss NBC Sports Boston's coverage of Pistons-Celtics, which tips off Wednesday at 6 p.m. with Celtics Pregame Live, and then Mike and Scal have the call at 7 p.m. You can also stream the game on the MyTeams App.