Howard finished with 19 points and 12 rebounds in 33 minutes of action in Los Angeles' 99-92 loss.
Howard made it through the Lakers' morning shootaround without any setbacks and had been listed as a game-time decision earlier Sunday.
Lakers coach Mike Brown said the final decision on whether Howard would make his Lakers debut Sunday night was made by head trainer Gary Vitti, just six months after Howard had major back surgery to repair a herniated disk.
"I thought he could have played, again from my knowledge and experience, from the beginning of training camp because he's played well and he's participated in almost everything we've done for awhile," Brown said before the game.
Howard appeared upbeat in the locker room before the game, joking with teammate Jodie Meeks, but he did not speak to reporters.
Brown said there would be no minute restrictions on Howard and he expects the All-Star center to be available for the Lakers' two remaining preseason games -- Wednesday against the Los Angeles Clippers at Staples Center and Thursday against the Kings in San Diego.
Sunday marked the first time the much-anticipated starting five of Howard, Kobe Bryant, Steve Nash, Pau Gasol and Metta World Peace played together. Brown said he wanted to see his starting unit play together at the opening tip, to end the second quarter, to start the third quarter and to finish off the game in the fourth.
The Lakers started out the preseason 0-5 with Howard out of the lineup.
"I hope we can win, especially trying to play as close to a rotation as possible, but if we don't again, it's not the end of the world," Brown said. "It's just more things that we may have to fix."
Forward Jordan Hill (back) will not play in Sunday's game. Hill was cleared for full-contact on Saturday for the first time since suffering a herniated disk Oct. 6.
"I almost got a little excited watching Jordan play last night and I then told myself to back off, just wait until Gary tells me that Jordan is ready to go," said Brown.
ESPNLosAngeles.com's Ramona Shelburne contributed to this report.