BOSTON — As Marcus Smart warmed up Saturday night to play against his former team for the first time, his wife, Maisa, had her hands full in the TD Garden front row. She was carrying their 2-month-old son, Zayn, and showing him off to a line of old friends.

According to Smart, the couple planned for Zayn to leave the arena before tipoff. Still, Smart considered it important to bring his first-born child to the building he used to call his home court. Smart wanted to introduce Zayn to his former teammates and Boston Celtics staff members for the first time. Plus, Smart told The Athletic, he wanted to create memories for father and son to look back on in the future.

“It’s going to be something when he grows up I can show him and he can understand it as he gets older,” Smart said.

After his usual pregame warmup, Smart posed for photos with Zayn and Maisa courtside. Years from now, Smart intends to show Zayn pictures and videos of the night his father first competed against the Celtics in the city where he spent the first nine seasons of his NBA career. Though Zayn couldn’t understand everything Saturday night, when Boston fell to the Memphis Grizzlies 127-121, Smart wanted his son to experience the love inside the arena.

“One day,” Smart said, “he can understand, he can see the impact his dad had on the city and on the team where he started his journey.”

Smart never missed the playoffs with the Celtics. He helped them reach the Finals in 2022 and the Eastern Conference finals four other times. He ranks fourth in franchise history in career steals and fifth in made 3-pointers.

But for as much as Smart gave the franchise on the court, his connection with the city of Boston extended far beyond his athletic accomplishments. The fans fell in love with him for his ferocity as a competitor. For the intensity of his emotions. For his willingness to dive on the floor and play through injuries and engage in whatever fight his team needed him to tackle. He donated time and resources to local hospitals and poured himself into the community.

“The ultimate Celtic,” Jayson Tatum said. “He’ll always be a Celtic for life.”

Smart plays for the Grizzlies now. Injured for both games against the Celtics last season, Smart had never suited up against them before Saturday. With 8:50 left in the first quarter, he checked in to a standing ovation. He raised his arm to acknowledge the loud reception, then walked across the court to defend Tatum. Perhaps impacted by the emotions of the night, Smart scored just 3 points on 1-for-11 shooting.

Smart has made peace with the Celtics organization’s decision to trade him in a three-way move for Kristaps Porziņģis and two first-round picks in 2023. Basketball-wise, Smart considers the trade a great one for Boston. The news of the deal still hurt at the time. Like Tatum, who said he never envisioned playing without Smart, Smart saw himself staying in Boston. He wore his hair green. He played the game with heart and unselfishness, two traits the city values most. The Celtics went 25-57 the season before drafting Smart. He helped pull them back into contention and keep them there throughout his tenure. Shortly after the trade, Brad Stevens told Smart, “The greatest legacy you can leave is to be someplace and it’s better off because you were there.”

“And I think that everybody here feels that way,” Stevens said then.

Though Smart didn’t win a ring in Boston, organization members believe he helped build the foundation of the team that did.

“I always say that the people who moved the Celtics forward are what make this job what it is,” Joe Mazzulla said. “Even before I got here, he just put his mark on the city with the way the fans responded to him, the way his teammates cared about him. Just how hard he plays every night. So to me, it’s a chance to thank him for that and for the people that have come before us.”

Before the game Saturday, Smart said congratulations to staff members he hadn’t seen since the team won the finals in June. Despite what must have been a bittersweet feeling of seeing his former team win a ring after trading him, he said he was very happy for the Celtics when they ended a 14-year championship drought.

“Obviously, you want to be a part of it, but sh– happens, excuse my French,” Smart said. “Sh– happens. You’ve just gotta move on. There’s no hard feelings. I know what those guys have been through. I know what they’ve sacrificed. So I’m just proud to see that they finally reached their goal.”

If not on the other side of things, Smart likely would have appreciated the Celtics’ effort Saturday, if not always their execution. During their fifth game in seven nights, they summoned enough energy to come back from a 14-point second-half deficit despite shooting poorly for much of the game. They gave themselves a chance to win by securing 15 offensive rebounds, including 11 in the second half, before sputtering late in the fourth quarter.

“These are the games you’ve just gotta fight through it,” Jaylen Brown said. “Tough schedule, but we don’t make any excuses. We know what the journey is about and we’re not skipping any steps. I thought we fought as a team. We didn’t let the rope go. We didn’t give up. Definitely, some shots didn’t go in. A very ugly game — turnovers — it just didn’t feel like a normal Celtics game. But I’ll give us credit: We fought. We fought until the end.”

Like Smart would have. For him and the Celtics, Saturday night was about more than just basketball. It was a chance to see family again. Brown called it weird to square off against his old friend.

“But it was great,” Brown said. “Marcus is a family member at this point. So to be able to see him, congratulating him on him starting his family, et cetera, off the court, is amazing.”

Unfortunately, not everybody on the Celtics got to meet Zayn. When Derrick White saw Maisa before the game, she told him they had just taken the baby back to the hotel. White said it still meant a lot to him that Smart wanted to introduce his child to the Celtics.

“When you become a parent, you kind of want to show your kid off,” White said. “And I think he saw all of us become parents and then he entered into that world. And we’ve kind of seen him and Maisa’s relationship over the years. I wish I met him. I’m sure he’s adorable. Just congratulations to them both.”

The memories of Saturday should stick with Smart forever. One day, he will tell the story of the night to his son. The story of how the city wrapped Smart in love once more.

“I think my legacy is going to speak for itself,” Smart said. “I don’t know what the end of my legacy will be here, what story will be told. But I know I’ve done my part and I think I made a great enough impact that it should be a good one.”