Al Horford didn’t begin his Celtics career in a vacuum. From his friendship with David Ortiz, to conversations Pedro Martinez had with his parents, to a frank warning from his new boss, Danny Ainge, Horford knew all about the Boston market and what happens when big money and impatience drive expectations.

“Danny told me things like, ‘Hey, fans here are definitely tough,’ ” Horford said recently of the warnings that came with signing a four-year, $113 million contract with the Celtics last summer.

Though Horford is proud of his ability to screen out game-night noises and distractions — masking his thoughts with an impassive game face — he started to hear things the night of a Jan. 6 game against Philadelphia at Garden.

These Sixers, despite a roster of young talent that included an exciting center in Joel Embiid, were now considered walkover material by the Celtics public. And when Embiid started hot, hitting five of his first seven shots, including two 3-pointers, the contrast was noted down the other end, where Horford began by missing his first five shots and six of his first seven.

Horford was especially on edge at the rim during this stretch, missing a pair of layup attempts, one blocked by Nerlens Noel, and two other shots within 9 feet.

“There weren’t boos, but you could feel the bickering in the crowd, like ‘Errr, Errrrrrrrr,’ ” he said, quietly laughing as he tried to recreate the sound of disgruntled mumbling.

“After a shot, I’m like, ‘Really? I know I’m 1-for-6 or whatever,’” he said. “They weren’t happy with me, I could sense it. They weren’t saying anything to me, but you could feel the energy. I felt like, ‘Hey, things are going bad, but you have to hang in there with me.’ Then, later in that game, coach threw me in in the fourth and I got hot; hit a bunch of shots. I hit a corner 3 to seal the win, and it was a little redemption for me.”

Horford’s game-winner from 24 feet came at the end of a 5-for-6 fourth-quarter run that included 4-for-5 from beyond the 3-point arc.

“When I started hitting shots, all that bickering went away,” he said. “Kind of cheering, and as I kept hearing them, the cheers grew louder.”

This 48-minute mood swing followed Ainge’s road map right down to the shift from groans to approval.

“Of course people were trying to get to know me,” said Horford. “With the contract, people get caught up in it, and I understand it. They expect greatness, and I expect it, too. I want to be that as well.”

Horford’s deal has been season-long fodder for talk radio and discourse among fans, where the debate continues over his sub-par rebounding numbers, limited inclination to score, and how the sum of his highly refined playmaking skills and efficiency transformed the Celts offense this year.

That argument probably will cover the length of that contract, or until the Celtics win another NBA championship.

And Horford’s placid, game-ready demeanor won’t change.

Legendary guidance

Pedro Martinez first met Horford’s mother, Arelis Reynoso, as a young Montreal Expos pitcher. She would visit the future Red Sox legend during road trips to Philadelphia, and when she married Tito Horford, the most famous basketball player in the Dominican Republic, Martinez became a non-blood uncle.

Al Horford grew up as a member of Dominican sports royalty due to his father’s status as the first Dominican-born to reach the NBA, and soon entered the sphere of celebrities like Martinez, a national hero.

And as Martinez remembers it, little Al never veered from that securely moored personality.

It’s with open affection that Martinez now says of the Celtics center, “He’s always been quiet, with a beautiful smile. There’s an angel in that big man. Kind of shy, to be honest.”

The family moved to Michigan, where Horford, now with his father’s towering size, rose through high school and two national championships at the University of Florida to NBA prominence. Like Karl Anthony-Towns after him, Horford was the toast of an island nation with a baseball for a heart.

But if anyone can steal attention away from the national Dominican pastime, it’s an international beauty queen, Amelia Vega, Miss Dominican Republic in 2003. She went to the Miss Universe Pageant that year, and returned from Panama City wearing a crown. Vega was also a singer and actress whose uncle-in-law, Juan Luis Guerra, is a singer and composer who has won two Grammy awards and 18 Latin Grammys.

When Horford married Vega in 2011 after a two-year courtship, another power couple was born. That rarified existence explains why Martinez is so proud of Horford and Vega, now with two young children and living in a western Boston suburb during the season.

“They’re just true Dominican people, very humble people who prefer to stay under everyone’s radar,” said Martinez. “Neither of them bothers to be in the eye of the public. They truly love their country, though.”

Knowledge of Horford’s easy, secure relationship with fame and status is one reason Martinez knew he wouldn’t be soured by a sports market as discerning as Boston’s.

“I knew he would adjust to Boston,” said Martinez. “I knew the atmosphere here would make him feel welcome. I know the kind of kid that (Tito and Arelis) raised. They were really good parents and were able to educate him the right way.”

Martinez says this while also being aware of Horford’s critics, a more forceful lot prior to his impressive postseason performance this year.

“I wouldn’t panic with this kid,” he said. “It’s all about his heart and IQ. He’s very dedicated to his work. When he got hurt (with a concussion) this year, you saw it. He came back with a vengeance. If he’s fine, he’s going to perform. His mind is never wandering out there. He’ll be fine here.

“This is good for him. There’s no better place to do something special than to do it in Boston.”

In perspective

One year into his max deal, Horford hopes fans have a better grasp of his unusual combination of size, skill and unselfishness.

“I feel it,” he said of the criticism. “Some of the stuff got through to me. Just the points and rebounds, I need more of that, I heard a lot of that. Trust me, I’m the first one who wants to do better. No question. But winning is more important.

“Playoffs are a time of year when you have to do whatever it takes to win, and at times that means getting more rebounds, or scoring more points, and defenses play you differently,” said Horford. “Some things you think are there, they take away from you, and you have to find another way. Sometimes it’s not about you scoring all the points, it’s about you sacrificing for a teammate.

“I feel Isaiah (Thomas) did a great job of that in the Washington series, with them trying to double him. Setting screens for me, getting me shots. People don’t always understand that there’s more than just scoring the ball.”

Horford also understands that big contracts will forever be tied to big scoring, and that outside noise is there to be muffled.

“My biggest thing, and I learned this at an early stage in my career, was to not read any of that information or see anything, good or bad,” he said, adding that talk radio is not part of his diet. “I definitely don’t do that, but in general I just stay away from it. One day people love you, the next they hate you, it’s really up and down, and my focus was making sure the team kept getting better as a group, and not worry about anything outside. One thing that helped me was not paying attention to a lot of things.”

That’s because Horford feels secure.

“I never did feel weight from my contract,” he said. “The reason was because Danny Ainge at the very beginning told me, ‘We signed you for who you are. Help us win, help us grow as a team. You don’t have to worry about numbers or anything.’ I don’t think people necessarily understand with contracts and everything that I had an opportunity to go to a couple of other really good teams — Houston, Washington, Atlanta. I had the options.

“For me, it wasn’t an easy decision, but when I looked at what we (the Celtics) had, I liked their fight, their will, how they played, and I just felt we had a chance to do some special things.”