Now he was little more than an hour from facing them for the first time as an NBA head coach, and even for a mostly meaningless preseason game, this was something special for him.
"You can't help but pay attention a little bit more and feel a little different," he said, "especially when . . . you grow up in that part of the world."
The moment may have been memorable for Brown, but aside from his personal history and the novelty of the game's site, the night was most significant as a symbolic starting point.
The Sixers' 97-85 victory was just one of what will be many tiny steps in their protracted rebuilding process - a process that the Celtics are beginning, too.
One had only to notice the most recognizable players on the floor Friday - Thaddeus Young, Jeff Green, Evan Turner, Kris Humphries - to understand how far away these two teams are from the league's elite.
"How dramatic their build vs. ours will be, who knows?" Brown said. "But I think philosophically, the programs are trying to do it in a similar way."
That the Sixers and Celtics are on parallel paths back to respectability is nothing more than the reality of the NBA. The league's salary cap and the impact of even a single superstar often force a franchise to gamble that, by breaking apart its roster and struggling for a season or more, it will increase the odds that it will draft a player who can change everything. (A simpler way to say all this is that the league encourages tanking, but that's well-trod ground.)
For too many years, the Sixers were unwilling to accept this necessary evil. They didn't want to bottom out, so they lingered on the periphery of the playoffs, sometimes reaching the postseason, sometimes missing it, usually inspiring little more than a shoulder shrug from frustrated fans. Everything about them became stagnant and stale.
It was only after their failed attempt to "go for it" last season - their misbegotten trade for Andrew Bynum - that they effected the overhaul in front-office personnel and philosophy they needed.
"This year is going to be a lot about development - bringing some of our young guys along, try to change the culture, what hard work looks like, what expectations look like," Sixers general manager Sam Hinkie said. "We're looking as long-distance as we can, vs. next month or next year."
At least the Celtics got to lengthen their legacy before hitting the restart button. With point guard Rajon Rondo and their trio of eventual Hall of Famers - Paul Pierce, Kevin Garnett, and Ray Allen - they won a championship in 2008, then reached the NBA Finals in 2010 and the Eastern Conference Finals in 2012 for good measure.
But after bowing out in the first round last season, they remade themselves. Allen already had departed for the Miami Heat. General manager Danny Ainge traded Pierce and Garnett to the Brooklyn Nets. Coach Doc Rivers left for the Clippers, and Ainge hired Brad Stevens, the wunderkind from Butler, to shepherd the Celtics through this transition. He will have to grow on the job. He knows this.
"There's a ton of differences" from the college game, Stevens said Friday, "everything from nuances of how the game is called from a physicality standpoint to the offensive nuances to the defensive nuances that you have to know. It goes all the way through."
Brown won't have as much learning ahead of him. He spent 11 years with the league's model for sustained success, the San Antonio Spurs, and he was around Gregg Popovich and Tim Duncan long enough to recognize that nights like Friday do have some meaning, even if it's not evident in the here and now.
"We're trying to build something out of each little window," he said. Those memories of his youth may have made Friday night special, but it was still just his third preseason game as the Sixers' head coach. The regular season doesn't start for another 2½ weeks. The long, slow ride back has only just begun.