Got his start in golf at a 9-hole course in Knowlton, Quebec, Canada, which is about an hour east of Montreal. The family spent about a month there every summer in Campbell's youth, as his father, Don, is from Montreal.

Got his first golf lesson from Dan Anselmo at Strawberry Farms Golf Course in Irvine, California. Dan is the son of John Anselmo, who is known for serving as Tiger Woods' coach for seven years (1987-1993).

Grew up in Irvine, California and attended Mater Dei High School in nearby Santa Ana. Mater Dei also produced Heisman Trophy winner and former NFL quarterback Matt Leinart, Heisman Trophy winner and No. 1 overall pick in the 2023 NFL Draft Bryce Young, as well as NFL All-Pro wide receiver Amon-Ra St. Brown, and former NFL quarterback Matt Barkley.

After finishing as low amateur at the 2015 U.S. Open at Chambers Bay, received a congratulatory message from Chicago Blackhawks defenseman with the same name, Brian Campbell.

Spent roughly seven years (2015 post-college through 2022) living in Costa Mesa, California. Campbell and PGA TOUR winner Jake Knapp lived together for the last couple years of Campbell's time there, with the two sharing a house at the end of the driving range at Mesa Verde Country Club.

Brother, Derek Campbell, played baseball at University of California-Berkeley and was twice selected in the MLB Draft (36th round to the Chicago Cubs in 2013, then the 20th round to the Philadelphia Phillies in 2014). Derek advanced as high as AA in the minor leagues and last played minor league baseball in 2017.