"I just wanted to establish being physical and being aggressive on defense," said White, who finished with five points, three rebounds, and five fouls over 9 minutes, 40 seconds of playing time. "So it was probably being more overaggressive more than anxious."
It was widely believed that White's perceived fear of flying due to an anxiety disorder contributed to his failure to play in the NBA last season.
White, acquired in a July trade with the Houston Rockets, was the 16th overall pick in the 2012 draft. The 22-year-old ex-Iowa State star last practiced with the Rockets Nov. 10 and played 16 games with the Rio Grande Valley Vipers, the Rockets' NBA Development League affiliate.
His only action with the Rockets came during two preseason games.
"I was happy to be out there," White said of participating in another NBA game. "I think I played well. I'm still not kind of making plays that are routine for me."
White committed three turnovers while driving to the basket.
"That's just a feel thing," he said. "I have to get the ball back."
White did show promise.
His first basket came after he grabbed a defensive rebound and went coast-to-coast for a layup. Then he added a late dunk.
"It's fantastic to see him on the floor," Sixers coach Brett Brown said. "That was my thrill."
The coach said he would have taken White out sooner had it been a regular-season game.
"I didn't care if he fouled out," he said. "You are just going to play him and let him play. Just to let him get out and play with his teammates and play an NBA game is exciting for him and for us.
Sixers forward Thaddeus Young led all scorers with 20 points. Center Spencer Hawes (17 points), guard James Anderson (16), and swingman Evan Turner (12) were the team's other double-figure scorers.
Reserve forward Jared Sullinger led the Celtics (0-3) with 19 points.