The Catholic identity of Boston Celtics coach Joe Mazzulla first came to light three years ago when he responded to a reporter’s question about Prince William and Kate Middleton sitting courtside at an NBA game in Boston’s TD Garden.
Asked what it was like to be in the presence of England’s royal family, Mazzulla responded, “Jesus, Mary and Joseph? … I’m only familiar with one royal family. I don’t know too much about that one.”
It was a beautiful response that flummoxed secular sports reporters who generally dislike writing about faith.
Mazzulla wasn’t asked about that comment on Thursday evening, Sept. 11 as the featured guest for Columbus St. Charles Preparatory School’s ninth annual An Evening With … speaker series in the Walter Student Commons, but he provided a glimpse into how he lives out his Catholic faith as the coach of one of the most iconic sports franchises in the world.
After answering questions from St. Charles students earlier in the day, Mazzulla sat down for a Q&A session with Paul Keels, the radio play-by-play voice for Ohio State University football and men’s basketball, as hundreds of guests in attendance listened attentively. Mazzulla then took several questions from the crowd.
In the sports world, few athletes and coaches are willing to openly talk about their Catholic faith because they fear persecution and backlash. Kansas City Chiefs kicker Harrison Butker and Notre Dame football coach Marcus Freeman are two exceptions that come to find who aren’t afraid to share their Catholicism in public.
Albeit Thursday’s event was held at a Catholic high school with mostly Catholics or Christians in the audience, the typically reserved Mazzulla wasn’t shy about expressing how his faith has set a foundation that allowed him to rise through the ranks from a college player at West Virginia University to a coach at two NCAA Division II schools and then in the NBA.
Speaking at a students-only session on Thursday afternoon reminded Mazzulla, 37, who attended a Catholic high school in Rhode Island, the importance of education in his formation.
One of the most impactful relationships he developed in high school was with the chaplain, who became a mentor and friend. The two have stayed connected for the last 20 years.
“I developed healthy habits there and one of them was going to the chapel,” he said in response to a question from the audience. “That’s where I fell in love with the rosary and where I fell in love with the chapel was during my freshman year. And those were habits that shaped me.”
Mazzulla shared that Catholic education afforded him an identity and the ability to develop a faithful relationship with Christ.
“You do need development with the spiritual courage to make great decisions,” he said. “And then there is having the right examination and knowing who you are, knowing what your purpose is, knowing that we all have different gifts, abilities and purpose on this earth, but I think we have a responsibility to push that purpose as far as we can to make people better. …
“We have a responsibility to the person next to you to help them win, but at the same time help them grow” whether it’s a player, colleague, chef or janitor.
Mazzulla said he has developed healthy spiritual habits to carry him through difficult situations. He carries a rosary with him and spends at least 20 minutes a day in silence that helps him deal with the pressures of the job.
“I think the more that you can have small prayers, small moments of wisdom, humble yourself before the next opportunity,” he said.
He prioritizes the sacrament of marriage and starts the day in prayer with his wife and two children.
“My main responsibility is my relationship to Christ and my second responsibility is to my wife,” he said. “If I don’t have the right relationship with Christ and I don’t treat my wife the right way, (my kids) are not going to have an example.”
He explained that anytime he and his wife buy or build a new house, it has to have a room that can be turned into a chapel.
“We start and end every day as a family in that chapel together,” he said. “I think that developing a relationship and teaching your kids how to have a relationship with Christ is the biggest gift that you can give them.”
Mazzulla came to the Celtics as an assistant in 2019 and not long afterward his father, Dan, a longtime high school coach, was diagnosed with cancer and died the following year at age 61. The juxtaposition of those significant events proved challenging.
“I had to really work spiritually to accept both of those things,” Mazzulla said.
“As I shared with the kids today, I feel like in life you have five or six moments where you have to prove to yourself that you are the person you say you want to be. And that was a moment I had to prove myself.”
Before the start of the 2022-23 season, Mazzulla took over as interim head coach when Ime Udoka was suspended. Later that season, Mazzulla was named the 19th coach in franchise history at age 34.
The Celtics lost a seven-game series in the Eastern Conference finals that year to the Miami Heat after falling behind 3-0 in the series.
“I almost broke spiritually and really identity-wise because I have my dream job, we’re down 3-0 and I’m letting the city down,” he recalled, before his wife gave him a reality check, saying, “you really thought you were going to win a championship your first year as an NBA coach? She coached me through that.”
The Celtics came back the following season and won the NBA championship in 2024. Mazzulla became the youngest head coach to win the title in more than 50 years.
His third year wasn’t quite as successful. The Celtics lost in the Eastern Conference semifinals in 2025, but after the season he received a multiyear contract extension.
He’ll begin his fourth season next month knowing that there will be ups and downs as the coach of a franchise with a proud legacy and high expectations. His Catholic faith helps him keep the big picture in perspective when the pressure becomes overwhelming.
“Just never shy away from the fact that I’m nothing without Him,” Mazzulla said, “and it’s all about trying to stay as close to Him as we can but really how quickly you can get back to Him when you do fall.”