He even did a grade-school book report on Jimmy, an aviation pioneer and leader of what became known as the Doolittle Raid during World War II -- the first air bombing raid to strike the Japanese home islands after Pearl Harbor.
It took until Friday, though, 72 years after the attack, for members of the Doolittle Raid to be awarded the Congressional Gold Medal.
"The more you learn about it, the more I was surprised it hadn't been awarded to them already," said Sean. "It's kind of a long time coming, but it's definitely well deserved."
Jimmy, it turns out, isn't some great, great uncle of Sean's, like the youngster originally was thought to believe. That much he knew when learning through research on several ancestry sites that Jimmy was an only child. Only recently did he discover Jimmy is his seventh cousin.
Jimmy passed in 1993, when Sean was 7 years old, and there remain only four surviving Tokyo Raiders of the original 80.
Sean took a tour of the USS Hornet Museum at nearby Naval Air Station Alameda last year, piquing his interest even more after viewing maps of the attack sites and photos from that fateful day commanded by Jimmy.
"It's been kind of rewarding for me, being in this area, going over to the Hornet a couple of times and learning about the Raid," said Sean, whose father, Rory, is retired Air Force. "It's pretty crazy. So awesome."
Jane Lee is a reporter for MLB.com. Read her blog, Major Lee-ague, and follow her on Twitter @JaneMLB. This story was not subject to the approval of Major League Baseball or its clubs.