Jason Chimera added a goal and three assists, and Nicklas Backstrom and Mikhail Grabovski each had three points as the Capitals (6-7) won for the first time this season when captain Alex Ovechkin didn't score a goal. Ovechkin didn't make the trip to Philadelphia because of an upper-body injury.
Washington had been 0-4 when Ovechkin, who entered Friday second in the league with 10 goals, didn't score.
Holtby made 30 saves.
Ward's third-period goal that made it 7-0 sparked a brawl. Just 9 seconds later, Philadelphia's Wayne Simmonds fought Washington's Tom Wilson. Flyers goalie Ray Emery then took on Holtby in another bout.
In the melee, a total of 114 penalty minutes were handed out. Overall, Philadelphia racked up 99 penalty minutes, and Washington received 65.
Holtby was perfect in handing the Flyers their first shutout loss of the season. Philadelphia (3-9) entered tied for last in the league with just 20 goals.
The Capitals didn't register their first shot until 4:56 remained in the first period. A little over two minutes later, Backstrom gave them the lead.
Nate Schmidt saved a Flyers clearing attempt and shuffled the puck to Martin Erat, who quickly passed it to Backstrom at the top of the right circle for a wrist shot over Steve Mason's glove.
Ward made it a two-goal advantage 1:24 into the second period, and less than a minute later, Chimera beat Mason on a breakaway. That prompted Flyers coach Craig Berube to pull Mason and replace him with Emery.
That switch made little difference as Emery promptly allowed another goal to Backstrom just 65 seconds after the goalie entered the game.
After Ward made it 5-0 at 16:25 of the second period, new Flyers forward Steve Downie - perhaps trying to spark his team in his debut - fought Aaron Volpatti.
While it earned applause from the crowd, Downie was handed an instigation penalty and a 10-minute misconduct. The Capitals took advantage, making it 6-0 on Troy Brouwer's power-play goal. It ended a streak of 15 straight penalties killed by the Flyers.
Washington, however, extended its penalty-killing streak to 30. Philadelphia was 0 for 5 with the man advantage.
Backstrom has 35 points, including 11 goals, in 22 career games against Philadelphia.
NOTES: Downie began his second stint with the Flyers, who acquired him Thursday from Colorado for forward Maxime Talbot. ... Flyers captain Claude Giroux has yet to score a goal through 12 games. ... Philadelphia will play at New Jersey on Saturday. ... Washington returns home after a season-high, five-game road trip to face Florida on Saturday.