At the age of four, Horn stood on cross-country skis for the first time. At eleven he switched to biathlon. After graduating from the Oberhof sports high school in 2014, he joined the Bundeswehr sports promotion group.
After a 17th overall place in the IBU Cup 2017/18 and a bronze medal in the individual at the EM , Philipp Horn was appointed to the World Cup team of German biathletes due to the victory in the mass start at the German Championships 2018 and gave on December 2, 2018 as part of a Mixed relay on the Slovenian Pokljuka made his World Cup debut. However, he was unable to perform well there and therefore had to switch back to the IBU Cup at the beginning of 2019. There Horn won then in Polish Duszniki-Zdroj his first race at the IBU Cup, a sprint. At the European Championships in Minsk he reached the silver medal with the German mixed relay. In the overall standings for the season , he came in tenth.
In autumn 2019, Philipp Horn qualified again for the World Cup team of German biathletes at the German Championship , but was able to significantly improve his performance compared to the previous year. He achieved his first two top 20 placements in Hochfilzen and his first podium in the World Cup with the men's relay. At the home World Cup in Oberhof , Horn finished sixth in the mass start and thus for the first time among the top ten, which means that he fulfilled the standard of the German Ski Association for the World Championships in Antholz . He made his world championship debut there, where he drew attention in the sprint with a very good cross-country performance and finished eighth. He also won the bronze medal with the German men's relay, the greatest success of his career up to that point. He finished his first full World Cup season in 18th place overall.
Germany
3.
Tyumen
Ridanna
Minsk-Raubitschy
Kontiolahti
Obertilliach