Trofimow began his international career in July 2007 in the FIS Cup in Bischofshofen . From August 2007 he was part of the permanent squad for the Ski Jumping Continental Cup . On December 20, 2008 he made it onto the podium for the first time with a 2nd place in Liberec . At the Junior World Championships in 2009 in Štrbské Pleso he jumped from the normal hill to 23rd place and reached 15th place with the team. On February 6, 2010 he started in Willingen for the first time in the ski jumping World Cup , but only reached 48th place. At the Russian Championships 2010 in Siberia, Trofimov won the title on the normal hill and the large hill with a clear lead.
Trofimow held the hill record on the K120 of the MS 1970 in Štrbské Pleso with 101.5 m from August 10, 2008 to September 13, 2009 . At the World Cup jumping on December 19, 2010 in Engelberg , he was able to achieve his first World Cup point with a 30th place. On November 27, 2011 in Kuusamo he achieved third place with the Russian team and thus his first podium finish.
At the Winter Universiade 2013 in Predazzo, Italy, Trofimov won the silver medal with the Russian team on the normal hill. He also took twelfth (normal hill) and 30th (large hill) place in the individual competitions. Four years later, he and his compatriots Alexander Baschenow and Mikhail Maximotschkin even won gold in the team competition against Slovenia and Poland.
On December 1, 2018, he was able to win World Cup points at the World Cup competition in Nizhny Tagil as 26th for the first time since the 2010/11 season and at the same time achieve his best individual result to date. At the 2019 World Championships in Seefeld in Tirol , he was 39th on the normal and 43rd on the large hill. With the Russian men's team, he finished ninth in the team competition.
In mid-September 2019, Trofimow became Russian champion on the normal hill of RusSki Gorki in Sochi .