BJ Flores distinguished himself early in his career by securing the National Golden Gloves light heavyweight championship in 1997, followed by back-to-back National Amateur heavyweight championships in 2001 and 2002. He made his professional boxing debut on May 3, 2003, in Las Vegas, Nevada, achieving a first-round TKO victory against Dallas Lane. Flores swiftly built his professional record with further TKO wins against Gabriel Taylor in 2003 and John Turlington in 2004, alongside a notable draw against Semisi Bloomfield in 2003. His ascent in the cruiserweight division continued in 2006 when he defeated Ali Supreme to claim the vacant WBF All-Americas cruiserweight title.
Throughout this period, Flores also challenged for major world titles, competing for the IBO Cruiserweight Championship against Danny Green in 2010. Flores later contended for the interim WBA World cruiserweight title against Beibut Shumenov in 2015, and the WBC cruiserweight world title against Tony Bellew in 2016. His final professional bout in 2018 saw him challenge Trevor Bryan for the vacant interim WBA heavyweight title. Concurrent with his fighting career, Flores began a successful transition into media, serving as a respected Ringside Analyst for Premier Boxing Champions on NBC since 2012, providing expert commentary on high-profile boxing events.
Since concluding his professional fighting career, Flores has expanded his expertise into professional coaching. From 2021 to 2023, he notably served as the boxing trainer for prominent personality Jake Paul, guiding him through multiple high-stakes fights. As a versatile and experienced figure in combat sports, Flores continues to leverage his deep understanding of boxing both behind the microphone as an analyst and in the corner as a trainer, solidifying his reputation as a multifaceted talent within the industry.