It worked in Sunday's 5-3 win over Baltimore, as Harris turned in a 3-for-4 outing with a double and solo homer. That earned the 30-year-old veteran an encore as the Nationals arrived in South Florida for the start of a three-game set against the Marlins.
"That's his attitude [to lead off], and he likes that," said Acta, who made it clear he wasn't ready to make the move sound like anything permanent.
"It's just one game, guys. We still have to wait and see."
If nothing else, the Nationals now have one of their hottest hitters in a more productive spot in the lineup. Harris came into Monday's game on a 12-for-35 tear (.343) over his past nine games, including three homers and five doubles.
The move allowed Acta to push his next four hitters down one slot -- Cristian Guzman second, Nick Johnson third, Ryan Zimmerman cleanup and Adam Dunn fifth. That order remained intact for Monday night's game.
"We're just trying to put as many guys with a high on-base percentage in front of Zimmerman and Dunn and lengthen our lineup," Acta said.
The Nationals haven't been able to generate much production following Dunn, with Acta noting the loss of catcher Jesus Flores (shoulder bruise) and inconsistency among the outfielders. Austin Kearns is hitting .150 over his past 30 games, while Elijah Dukes is in a 4-for-31 slump.
The struggles created an opportunity for Harris, whose start in center field was his 15th in the Nats' past 16 games. The move immediately upgraded Washington's defense, and Acta eventually noticed Harris was producing at the plate as well.
"It helps that Willie has been playing more," Acta said. "That's what made [the move] easy. You can't just put a guy up there to put him there because he can run."
Acta acknowledged he'd been considering moving Harris into the leadoff spot for a week before finally pulling the trigger. What kept him from doing it earlier?
"I guess just a pen and a piece of paper," Acta deadpanned. "I just said [Sunday], 'I'm going to do it right here.'"
No matter to Harris. After finally sticking in the big leagues for an entire season last year with the Nationals, he's learned to appreciate whatever opportunity he gets.
"It doesn't really matter where I hit, where I play," Harris said. "The last couple of weeks or so have been really good for me -- I've been able to get some hits and score some runs. That's the only thing I care about, my on-base percentage and runs scored."
Harris also is adept at working deep into the count, as evidenced by the 22 pitches he saw in his first three at-bats against the Orioles.
"I treat my first at-bat as not really my at-bat," Harris said. "That's for my teammates to see what this guy [on the mound] is doing -- to see his velocity, hopefully see all his pitches."
It paid off with a victory Sunday. Now it'll largely be up to Harris to see how long the trial runs.