Lombard was born on the Gold Coast into a family with a Cuban father and an Australian mother. He attended Varsity College throughout his upbringing and took part in their ASPIRE AFL excellence program with future Suns teammate Jake Rogers.[2] Lombard's father, Héctor, is a professional mixed martial artist who competed in the Ultimate Fighting Championship[3] and a formerly competed as an Olympicjudoka who represented Cuba at the 2000 Sydney Olympics. His father introduced him to Brazilian jiu-jitsu at six years of age[4] and Lombard was considered a promising prospect years later when he claimed a gold medal at the Pan Pacific Championships in 2017 and was crowned the under-12 BJJ Australian Open champion in 2018.[5] He also began playing Australian rules football at eight years of age for the Burleigh Bombers and excelled as a junior footballer, which was rewarded with an invitation to join the Gold Coast Suns Academy at 12 years of age.[6]
Lombard later admitted he only played football "for fun" on the side and was focused on pursuing a career in mixed martial arts, until the greater levels of development opportunities provided by the Suns Academy convinced him to quit Brazilian jiu-jitsu and chase a career in the AFL.[7] Lombard progressed his way through the Gold Coast Suns Academy junior grades earning representative honours along the way such as being selected in the 2022 U16 All-Australian team.[8] In 2023, he was selected to represent the victorious Allies team as a bottom ager in the U18 National Championships alongside future AFL teammates Jed Walter, Ethan Read, Jake Rogers and Will Graham.[9] Lombard capped off his 2023 season by taking part in the Gold Coast's VFL grand final winning side at 16 years of age.[10] He returned to the U18 National Championships a year later and was awarded the Larke Medal as the best performed Division I player in the country as well as selection in the starting U18 All-Australian team.[11]