The Washington Nationals and general manager Mike Rizzo announced Matt Williams as the fifth manager in Nationals' history. (Nick Plum for Synthesis/Koubaroulis LLC./The Washington Post)

Friday morning, about 12 hours after he took his 9-year-old daughter Madison trick-or-treating on Capitol Hill, Matt Williams reported for his first day as Washington Nationals manager. He signed his contract to make it official. He shook hands with Mayor Vincent C. Gray. He strolled through the Nationals’ offices and met employees, at one point sneaking up behind a corporate relations staffer to frighten her as a prank.

In the afternoon, he walked into a room in the bowels of Nationals Park for an introductory news conference, complete with radio man Charlie Slowes as emcee. “The right man at the right time for Washington D.C.,” General Manager Mike Rizzo said, as if Williams may decide he wants Gray’s job instead.

Williams sat next to Rizzo at a dais. In the front row sat Ted Lerner and the rest of the team’s ownership family; players Jayson Werth, Ian Desmond and Tanner Roark; bench coach Randy Knorr; plus Madison and Williams’s wife, Erika.

Williams pulled a No. 9 Nationals uniform over his gray shirt and olive tie. (Another Williams once wore No. 9 as a manager in Washington: Ted Williams, when he managed the Senators.) Camera flashes bounced off his bald head.

“Do a little spin,” a photographer said.

“On the catwalk?” Williams replied, smiling.

Once he sat back down and the questions came, Williams flashed the qualities that convinced Rizzo and the Lerners to hire him. He proved open to new ideas and expressed a plan in articulate, precise language. He offered gratitude toward ownership and thanked the players who had come in support.

“I was asked that question in the interview: ‘Why you?’ ” Williams said. “I think the simple answer for me is: I bring passion to the game that I love. This game has given me a lot, and I need to return that. So in whatever aspect of the game we find ourselves in, whether it’s offense, defense or pitching, whatever, I’m going to approach it with passion.”

Mostly, Williams eschewed typical news conference vagaries and platitudes for a specific plan, one based on strong defense, aggressive base running, exhaustive preparation and a players-first approach.

After calling Davey Johnson “a Hall of Fame manager in my book,” Williams shared his ideas on how to put his own stamp on a team with World Series aspirations.

“This is not a situation where you come in and something is clearly broken that needs to be fixed,” Williams said. “What I can say is that there are some things we can refine. I think we can play a little bit smarter baseball. I think we can use the tools that are given to us a little better.”

Williams will demand and coerce strong defense, aided by a new assistant coach who will determine how best to position fielders. Mark Weidemaier, a baseball lifer who spent the majority of his career as an advance scout, will follow Williams from Arizona and become the Nationals’ seventh coach. He will gather information from the Nationals’ video and scouting staffs and determine defensive alignments.

Williams mentioned his preference for exotic plays at the right moment: “I believe in the safety squeeze, man,” he said. “I really believe in it. We’ve got a pitching staff that handles the bat — can we hit-and-run with them?” He wants to steal frequently and will encourage runners to take extra bases. As Arizona’s third base coach, he once led the league in getting runners thrown out at home, a fact he raised not as a lament but a boast.

“I think that if you apply pressure, you have the advantage,” Williams said. “I will be aggressive. My natural tendency is to go.”

To overcome his dearth of experience and unfamiliarity with personnel, Williams promised he would lean on his coaching staff, especially Knorr. At Williams’s urging, Knorr flew from his home in Tampa to attend the news conference. Next week, Williams and Knorr will spend time together at the Arizona Fall League to discuss the roster.

Williams called Knorr on the night news of his imminent hiring leaked to ask him to remain on his staff as bench coach. Knorr accepted on the spot, swallowing his disappointment over not getting the job himself.

“I can see how people could look at that and maybe see that there could be some uncomfortableness,” Werth said. “But they don’t know Randy. And if you knew Randy, you could see how that whole thing could work. It takes a special person I would say, but Randy is a special person, and that’s why he got so many guys on his side and so many people that wanted him back here, no matter what.”

The rest of the Nationals’ coaching staff will return aside from one change. Class AA Harrisburg Manager Matt LeCroy, a longtime major league backup catcher, will replace Jim Lett as bullpen coach.

Williams cited Dusty Baker as a mentor for the way he treated players like men, manager and player on an equal plane. He vowed he would seek opinion from veterans such as Werth, Desmond and Ryan Zimmerman. Still, Williams likely will be more demanding than Johnson, who rarely lashed out at players.

“Davey was more laid-back,” Knorr said. “He has that in him, too. But there are going to be times that he’s not going to be laid-back, and he’s going to want things done a certain way. It’s going to shock them a little bit at first when it happens. And I think he’s going to be more hands-on and more one-on-one with them.”

Nationals players, hungry to return to the playoffs after an 86-win season following a wrenching playoff loss in 2012, appear open to Williams’s approach.

“This is really the first time I’ve had an opportunity to hear his game plan, and everything he said makes sense,” Desmond said. “I think it’s a breath of fresh air. We’ve played well over the last couple years and we haven’t got to the championship game. I think there’s nobody in our clubhouse or organization who isn’t open to trying something new.”

Said Werth: “I want to play for a guy that I do want to run through a wall for. But he’s got to be that guy. I think that he ultimately will be. He’s been in this situation where he’s been in my shoes. He felt the same way about a manager. I think he really understands both sides of it. I really think we got the right guy for the job.”