Culpepper was born into a family of University of Florida alumni. His father, Bruce Culpepper, was a center for the Florida Gators football team from 1960 to 1962 and co-captain of the Gators' 1962 Gator Bowl team, and became a prominent Tallahassee attorney. His uncle, Blair Culpepper, was a Gators fullback in 1957 and 1958, and became a bank president in Winter Park, Florida. His grandfather, J. Broward Culpepper, was also a Florida graduate and served as the chancellor of the State University System of Florida.
Culpepper met Monica Frakes in 1990, when he was a sophomore at the University of Florida. The couple married weeks after Culpepper was drafted into the NFL in 1992. Together they have three children.
Culpepper graduated from Florida with his bachelor's degree in history after his junior year, and enrolled in a master's degree program in exercise and sports sciences during his senior football season. After finishing his professional playing career, Culpepper returned to graduate school and law school full-time, and earned his master's degree and law degree from Florida in 2001. He was inducted into the University of Florida Athletic Hall of Fame as a "Gator Great" in 2001. The sports editors of The Gainesville Sun ranked him as the No. 47 all-time greatest player of the first 100 seasons of the Florida Gators football team in 2006.
Culpepper is now a trial lawyer for the Culpepper Kurland law firm in Tampa, Florida. Since his retirement, he has spoken out about his concerns regarding the increasing size of NFL players; he believes that the increasing number of 300-pound players is "unnatural and unsafe" and has led to many serious health problems. During his football career, Culpepper inflated his weight to 280 pounds; after he retired from professional football, he lost almost 100 pounds.
Culpepper's wife Monica was selected as a participant for the 24th season of the CBS reality television show Survivor, and she and Brad participated together in the 27th season of the show. Culpepper came in 15th place while Monica was the season's runner up.
On May 6, 2015, it was revealed that Culpepper was one of 16 men eligible to be voted onto Survivor's 31st season, Survivor: Cambodia. Also from Blood vs. Water were fellow newcomers Ciera Eastin and Vytas Baskauskas. The results revealed, on May 20, that Culpepper was the only one of the three to not make it into the season.