Spizow started in Vershina Tjoi for the first time in the Eastern-Europe-Cup in November 2012 and finished in 141st place over 10 km freestyle and 151st place in sprint. At the Nordic Junior World Ski Championships in 2014 in Val di Fiemme , he took 35th place in the sprint. The following year he won the bronze medal in the skiathlon , the silver medal in the 10 km freestyle and the gold medal with the relay at the Nordic Junior World Ski Championships 2015 in Almaty . In March 2015 he became the Russian junior champion in Skiathlon and over 10 km freestyle in Tyumen . At the Nordic Junior World Ski Championships 2016 in Rasnov , he won the bronze medal in the 15 km freestyle and the silver medal with the relay. He also achieved fourth place in the sprint. At the beginning of the 2016/17 season he achieved his first podium finish in the Eastern Europe Cup with third place in the 10 km freestyle in Vershina Tjoi. In the further course of the season he came under the top ten four times and thus finished tenth in the overall ranking of the Eastern Europe Cup. He won his first win in this racing series in the Syktyvkar skiathlon . At the U23 World Ski Championships in 2017 in Soldier Hollow , he won the 15 km freestyle and the bronze medal in the skiathlon. At the beginning of the 2017/18 season, he started in Davos for the first time in the cross-country skiing world cup and achieved 77th place in the sprint. The next day he got his first World Cup points with seventh place in the 15 km freestyle. He finished the Tour de Ski 2017/18 in 13th place. He achieved his first podium in the World Cup with the third fastest time in the final stage in the Fiemme Valley . At the U23 World Championships in Goms in 2018 , he won the silver medal over 15 km classic and the gold medal in the skiathlon. At the season highlight, the 2018 Winter Olympics in Pyeongchang , he won the bronze medal in the 15 km freestyle and the silver medal with the relay and together with Alexander Bolshunov in the team sprint. At the end of the season he reached tenth place at the World Cup finals in Falun and finally finished 20th in the overall World Cup and 15th in the Distance World Cup.
At the beginning of the 2018/19 season, Spizow achieved third place in the classic 15 km stage in the Lillehammer Triple, which he finished in 27th place, and second place in the relay in Beitostølen . At the Tour de Ski 2018/19 he came eighth with three top ten placements. In January 2019, he won his first World Cup victory with the relay in Ulricehamn . At the season highlight, the Nordic World Ski Championships 2019 in Seefeld in Tyrol , he finished 28th in the 50 km mass start race and 22nd place in the skiathlon . At the end of the season, he finished 37th in the World Cup finals in Québec, and then 18th in the overall World Cup and 16th in the Distance World Cup. The following season he finished 11th in the Tour de Ski 2019/20 and 21st place in the 2020 ski tour. In addition, he was second in Lillehammer and third in the relay in Lahti and reached 16th place in the Distance World Cup and 15th place in the overall World Cup.