Imboden was born in Tampa, Florida. His parents gave him his name after the Jonny Quest character Race Bannon. He moved to Atlanta at a young age. His first sports were inline skating and BMX; an inline skating accident left him with a crooked nose and a scar on his lip. He was playing with a toy sword in a park when a stranger suggested to his parents that he take up fencing. Shortly afterwards his family moved to Park Slope, Brooklyn, New York City.
Imboden joined the Fencer's Club in Manhattan, where he first met Jed Dupree and Dan Kellner, both of whom were foil fencing athletes in the 2004 Summer Olympics. Both men would later work with Race as a student. Imboden was educated at the Dwight School, which supported his budding sports career. He fought his first international competition at age 14 and later earned the bronze medal in the cadet (U17) world fencing championships in 2010. After graduating High School in spring 2011 he decided not to go to Notre Dame, with which he had signed a letter of intent, but to take a year off to focus on his training. He became a member of the Brooklyn Bridge Fencing Club, in the DUMBO section of Brooklyn, with Dan Kellner as his coach. He finally opted for St. John's University in New York, because it is closer to his family and coach.
He began modelling for Re:Quest Models after being scouted by an agent during the London Olympics. In 2013 he made models.com's "hot list" of the most in-demand newcomers in the business. In 2015 he began working with Wilhelmina Models. He left school during his freshman year to concentrate on his modelling and international career, as under NCAA rules he could not take part in collegiate fencing while being paid to model.
Imboden's other passion is hip hop. He interned at independent label Fool's Gold in 2012 and is a DJ in his spare time.
Imboden joined the national cadet (U17) team in 2010 and won the Cadet National Championship the same year. A year after, he came first at the Senior National Championship in Portland, Oregon and won the gold medal in individual and team foil at the 2011 and 2012 Pan American Fencing Championships. At the age of 17, he made the senior national team for the 2011 World Championships in Catania. For his first participation to an event of this magnitude, he reached the quarter-finals after seeing off triple world champion Peter Joppich, but lost to France's Victor Sintès.
At the beginning of the 2011–12 World Cup he earned his World Cup podium with a bronze medal in the Challenge International de Paris. His good international results had him named into the US Olympic team, which qualified him to the 2012 Summer Olympic Games in London as a member of the top-ranked team in the Americas zone. Seeded no.4, he finished 9th after being eliminated in the table of 16 by Andrea Baldini of Italy. In the team event, no.5 seeded USA prevailed over France, but lost to Italy, who eventually won the gold medal. They met Germany in the final for the bronze medal, but lost again and finished fourth.
In 2013 Imboden won the gold medal at the 2013 Copa Villa La Habana, his first World Cup title, breaking a 14-year drought of US Foil World Cup Champions. He is now one of two US men's foil fencers to have won a World Cup competition. In June of the same year he won a silver medal in the Pan American fencing Championships in Cartagena after being defeated in the final by his teammate Gerek Meinhardt. At the 2013 World Fencing Championships in Budapest Imboden was defeated in the table of 16 by Ukraine's Rostyslav Hertsyk, who later earned a bronze medal. He took part in the team event for the United States, who lost the final to Italy and took the silver medal. Imboden finished 10th in the 2012-13 FIE world rankings.
Imboden began the 2013–14 season win a silver medal finish in the 2013 World Combat Games. He won his second USA Division-1 National Championship title in April 2014, defeating David Willette 15-6. He placed second in the SK Trophée in Seoul and third in the Prince Takamado World Cup. The World Championships in Kazan were a disappointment as Imboden was defeated in the table of 16 by teammate Gerek Meinhardt. In the team event, No.4 seed USA lost to eventual silver medallist China in the quarter-finals and finished fifth. Imboden finished the season world No.10 for the second time in a row.
In the 2014–15 season Imboden made the quarter-finals in the San Francisco World Cup and proceeded to win gold at the Prince Takamodo World Cup in Tokyo after overcoming Russia's Dmitry Rigin in the final. He posted a third place in the Trofeo Inalpi in Turin, Italy. In January 2015 he achieved a double gold at the Challenge International de Paris: he became the first American to win the individual event after defeating Italy's Daniele Garozzo, then earned a second gold medal in the team event after Team USA prevailed over Italy. Imboden then took a bronze medal in the Havana Grand Prix. In April he won the Master de Fleuret in Melun, prevailing over Ma Jianfei in the final. Two weeks later he earned the gold medal at the 2015 Pan American Championships in Santiago, his third individual Pan American title. The 2015 World Championships in Moscow proved a disappointment: Imboden was defeated in the table of 16 by Olympic champion Lei Sheng. In the team event, the United States lost to Italy in the quarter-finals and finished sixth after the placement rounds. Imboden did, however, ended the season World no.1, ten points ahead of newly crowned world champion Yuki Ota, thus becoming the first American male fencer to win the overall World Cup.
In the 2015–16 season Imboden achieved another double-gold haul at the Paris World Cup, becoming the first fencer since Benjamin Kleibrink in 2006–2007 to win back-to-back editions. Three podiums out of three World Cup competitions sealed the United States' qualification to the team event of the 2016 Olympic Games in Rio de Janeiro, guaranteeing three American slots in the individual event. Despite a further bronze medal at the Havana Grand Prix and a no.4 world ranking, Imboden was overtaken in the US rankings and qualified to the Olympics only as a reserve for the team event.World Fencing Championships
Team silver, 2013 World Fencing Championships in Budapest
Pan American Fencing Championships
Individual gold, 2015 Pan American Fencing Championships in Santiago
Team gold, 2014 Pan American Fencing Championships in San José
Team gold, 2013 Pan American Fencing Championships in Cartagena
Individual gold, 2012 Pan American Fencing Championships in Cancún
Team gold 2012, Pan American Fencing Championships in Cancún
Individual gold, 2011 Pan American Fencing Championships in Reno, Nevada
Team gold, 2011 Pan American Fencing Championships in Reno, Nevada
Fencing World Cup (individual)
2015–16: 1 gold medal (Paris), 1 bronze medal (Havana)
2014–15: 2 gold medals (Paris, Tokyo), 2 bronze medals (Havana, Torino)
2013–14: 1 silver medal (Seoul), 1 bronze medal (Tokyo)
2012–13: 1 gold medal (Havana)
2011–12: 2 bronze medals (Paris, Seoul)
Junior World Fencing Championships
Team silver, 2013 Junior World Championships
Team gold, 2012 Junior World Championships
Team gold, 2011 Junior World Championships