If you feel like you don't really know Jimmy Garoppolo, you're not alone.

His pre- and post-game interviews are mundane. His Instagram is comprised mainly of game photos with the occasional ad peppered in: a local luxury car dealership, the Men's Wearhouse, New Era or Bose. He doesn't even have a "personal life" section on his Wikipedia page. With one major, TMZ-headlining exception, his private life has rarely entered the public arena.

He's as understated as a movie-star-handsome, on-the-brink-of-a-Super Bowl quarterback can be. And part of that business-first face is because of former teammate Tom Brady.

Although their relationship has at times been portrayed as contentious, Garoppolo is generous in his praise of Brady since leaving the New England Patriots. From Brady, he gleaned lessons that were less about football than they were about handling the scrutiny of the spotlight.

"While Jimmy certainly learned a lot on the field, he received the most advice from Brady off it," Bleacher Report wrote in 2018. From Brady, Garoppolo learned the "trick of a modern celebrity life, from the finances to the locker room and, of course, the women." The pair still text each other frequently, with Garoppolo generally asking for off-the-field advice from the six-time Super Bowl champion.

It's perhaps no surprise Brady had a lot of advice to impart on keeping your family out of the news. In his early NFL days, he was a regular tabloid feature due to his relationship  — and highly publicized breakup — with actress Bridget Moynahan. The pair's only child together was born months after they officially separated.

It's telling that the most expansive Garoppolo has been about his family was back during his college days. In a 2014 Sauk Valley Sports article, he spoke about his tight-knit Italian-American family; his grandmother Jane (who he calls "Nana") was the first generation born in America and the family lived his whole life in the same home in the Chicago suburb of Arlington Heights.

“My Nana – we call her Nana, actually, it’s Italian – was texting me right before this wishing me luck,” he said at the time. “It’s my mom’s birthday coming up, so we’re going to get together as a family. It’s a rare thing that we get everyone together, so when we get the opportunity, it’s awesome.”

Garoppolo is the third of four sons of parents Tony and Denise ("I thank my parents for the good looks," he joked once. "It’s the Italian tan, I guess.") Growing up, his dad worked as an electrician, leaving before sunrise every morning so he could get home in time to coach the boys' afternoon sports teams. Jimmy stuck close to home for college, choosing Eastern Illinois, a few hours' drive away. When Garoppolo was invited to the 2014 NFL Draft, it was the first time any of the family had been to New York City.

“None of us had been to New York ever — my parents included,” his brother Mike told USA Today. “So, it was like a whole new experience for us back then. We get there, and we’ve never been treated the way we were treated. Jimmy hadn’t, we hadn’t. It was insane."

There's other reason for Jimmy G's low profile: that through-line of his quiet personality. Profile after profile, year after year, repeat the same stories. In college, he didn't have a car so he walked 30 minutes to practice every day. He slept on the couch most days because his college rental was blistering hot upstairs. He gave up his bed to friends when they rented a hotel room for the NFL Draft — his special day.

Today, his 49ers teammates speak glowingly about his team-first mentality.

"We see him every day," Richard Sherman said in November. "We see what kind of work ethic he puts in, the hours he puts in preparing — the first one in, the last one out. The guy looks for no credit. All he does is encourage his teammates and put more work in."

Clearly, the quarterback is happy to let others have the sound bites.

"He really just flowed with the way everything went," his mother reflected to Bleacher Report in 2018. "So on vacations, he really never caused any kind of a problem. My other sons were more boisterous. Jimmy wasn’t."

Katie Dowd is an SFGATE Senior Digital Editor. Contact: katie.dowd@sfgate.com | Twitter: @katiedowd