Aymoz began learning to skate in 2003. He became the French national junior bronze medalist in the 2012–2013 season and repeated the following season.
2014–2015 season: Senior international debut
Aymoz started the 2014–2015 season on the junior level, winning gold at the Lombardia Trophy and bronze at the International Cup of Nice. Making his senior international debut, he finished eighth at the 2014 NRW Trophy at the end of November. He placed fifth on the senior level at the French Championships, held in December, before winning the national junior title, in February 2015. Aymoz ended his season with a senior international medal, silver at the Coupe du Printemps in March.
Early in the season, Aymoz was coached by Véronique Cartau, Bernard Glesser, and Jean-François Ballester in Grenoble. His ISU Junior Grand Prix debut came in late August 2015; he placed fourth at his sole assignment, in Riga, Latvia. After winning the senior bronze medal at the Lombardia Trophy in September, he made his first appearances on the ISU Challenger Series, placing seventh at the 2015 CS Tallinn Trophy in November and twelfth at the 2015 CS Golden Spin of Zagreb in December. In February 2016, Aymoz won his second French national junior title. In March, he represented France at the 2016 World Junior Championships in Debrecen, Hungary; he qualified for the free skate by placing fifth in the short program. He finished ninth overall after placing eleventh in the free skating. By the end of the season, he was training in both Grenoble and Annecy, overseen by Cartau, Didier Lucine, Claudine Lucine, and Sophie Golaz.
2016–2017 season: First national title
In the first half of the season, Aymoz was coached by Didier Lucine, Sophie Golaz, and Véronique Cartau in Annecy. In December 2016, he won the French national title. On 16 January 2017, the FFSG reported that Aymoz had decided to return to Grenoble and that the federation had sent Katia Krier for the intermediary period. He placed fifteenth at the 2017 European Championships in Ostrava, Czech Republic.
At his first event of the season, the 2018 CS Autumn Classic International, Aymoz placed eight in the short, third in the free, and fifth overall. Aymoz received two Grand Prix assignments, the 2018 Skate Canada International and 2018 Internationaux de France. He placed seventh and fifth, respectively. At the close of the year, Aymoz won his second French national title. At the 2019 European Championships, Aymoz placed fourth in both the short program and free skate, finishing fourth overall, and only 0.74 points behind bronze medalist Matteo Rizzo of Italy. At the 2019 World Championships in Saitama, Japan, he placed eleventh, setting a new personal best in the short program and total score.
Aymoz again began his season on the Challenger series at the 2019 CS Autumn Classic International, where he won the silver medal with second-place finishes in both segments. Aymoz landed two quads in a free skate for the first time. On the Grand Prix, Aymoz competed first at the 2019 Internationaux de France, where a fall on his combination attempt in the short program left him in third place, distantly behind Nathan Chen and Alexander Samarin but only a few points ahead of Shoma Uno. He placed second in the free skate, behind Chen, winning the bronze medal overall. Aymoz then continued this successful streak by winning silver at the following NHK Trophy and thereby qualifying for the Grand Prix Final. He was second in the short program behind Yuzuru Hanyu, making only a small error on his quad toe loop, and third in the free skate behind Hanyu and Roman Sadovsky. Competing at the Final, Aymoz placed third in the short program, skating cleanly despite a musical mishap that initially played the music of competitor Dmitri Aliev. Third in the free skate as well with only one error with a fall on an underrotated quad toe, he won the bronze medal, the first Frenchman to medal at the Final since Brian Joubert in 2006.
Small medals for short and free programs awarded only at ISU Championships. At team events, medals awarded for team results only. ISU personal bests highlighted in bold. Historic ISU personal bests highlighted in bold and italicized.