Frankie made his sevens debut at the 2007 Dubai Sevenstournament and immediately established himself as a key player for the team, appearing in all eight tournaments in the series.
He once again played every leg of the 2008–09 IRB Sevens World Series, as South Africa won the series. He also played in the 2009 Rugby World Cup Sevenscompetition, helping South Africa to the quarter-finals, where they lost to Argentina. He also won a bronze medal with the side at the 2009 World Games in Kaohsiung, Republic of China.
During the 2013 London Sevens, Horne played in his 50th consecutive IRB Sevens World Series tournament, becoming the first player to achieve this feat. He was also selected in the squad that played at the 2014 Commonwealth Games and helped his side to a 17–12 victory over a New Zealand that won the previous four tournaments.
