When Jayden Daniels showed up for his first preseason game with the Washington Commanders, he wore a Doug Williams no. 17 throwback jersey. That’s when his team should have known it had something special in its rookie quarterback.

“What better way to have my debut than to represent Doug and what he did for this organization,” Mr. Daniels said back in August.

Fast-forward to the present and Mr. Daniels has Washington one win from returning to the Super Bowl for the first time in 33 years — and 37 years since Mr. Williams became the first black quarterback to start and win a Super Bowl.

For Mr. Daniels, an African-American, wearing Mr. Williams’s jersey wasn’t as much about race as it was a symbol of the franchise’s return to its glory days, which the rookie quarterback is orchestrating along with the team’s new head coach, Dan Quinn, and a new ownership group headed by Josh Harris and the general manager, Adam Peters.

The Commander (12-5)  meet the division-rival Philadelphia Eagles (14-3) in the NFC Championship on Sunday at Philadelphia, with the winner heading to Super Bowl LIX to play the winner of the AFC Championship between the Buffalo Bills (13-4) and the three-peat-seeking Kansas City Chiefs (15-2).

No one is more proud of the Commanders and Mr. Daniels’s success than Mr. Williams, who serves as a senior advisor with the team. “He’s always poised,” Mr. Williams, the Super Bowl XXII MVP, told USA Today. “He’s always thinking. When you watch him, you know his mind is moving. He’s never under pressure, mentally.”

No rookie quarterback has ever started a Super Bowl, and Mr. Daniels is just the sixth to reach a conference championship game. Most rookie quarterbacks start for bad teams — like the no. 1 overall pick, Caleb Williams, who spent a frustrating rookie year with the Chicago Bears, who fell apart after Mr. Daniels beat them with a 52-yard Hail Mary pass to win the game, 18-15, in October. 

Mr. Daniels has led the Commanders’ resurgence by playing like a grizzled veteran. He passed for 3,568 yards and 25 touchdowns with nine interceptions during the regular season to earn a spot in the Pro Bowl. He has been electric in the playoffs, passing for 567 yards and four touchdowns with no interceptions in road wins over the Tampa Bay Bucs, 23-20, and the no. 1-seeded Detroit Lions, 45-31.

If Mr. Quinn, who won the NFC Championship as the head coach of the Atlanta Falcons, established a new culture, Mr. Daniels has galvanized the fan base by proving he is their long-sought-after franchise quarterback.

“He’s got rare in-the-moment skills that have allowed us to be in this spot,” Mr. Quinn said. “When there’s mental chaos going down, and two minutes left and things could be tight, he’s got the experience of somebody that’s played a lot more football than a first-year player.”

His poise under pressure has impressed his teammates. “He’s locked in from the start of quarter one to the end of quarter four,” wide receiver Terry McLaurin said. “He stays as even keel as any player I’ve ever been around. To have that demeanor as a rookie quarterback is one of the things that makes him so unique. Whether it’s a good play or a bad play, he’s worried about how we can execute the next play.”

The Commanders have won seven straight games since enduring a three-game losing streak in November that threatened to ruin their chances of making the playoffs. After undergoing a complete change — from ownership to the coaching staff — reaching the NFC Championship game is confirmation the team’s difficult years under Dan Snyder are long gone.

“This whole building has changed tremendously,” Mr. Williams said during an interview with “Good Morning Football.” “It’s fun to come to work because you don’t want to miss anything. Everybody sees we’ve got something good going on here.”

The Eagles could not care less. The NFC East rivals are meeting for the third time this season. The two split their regular-season games, with the Eagles winning the first in Week 11 when Mr. Daniels passed for just 191 yards and one touchdown with one interception. Mr. Daniels threw five touchdown passes in the rematch, won by the Commanders, 36-33.

Mr. Daniels insists he won’t be overwhelmed by the moment come Sunday at Lincoln Financial Field. “For me football is fun,” he said. “It’s like a safe haven for me. Everything I’ve been through personally in my life, I’m not really going out there and stressing. I get to do what I love each and every week, win, lose, or draw. It’s a blessing to be one of those kids that can live out their dreams of playing on Sunday in the NFL.”