[8] In early September 2019, Samsonov made his ISU Junior Grand Prix debut at the 2019 JGP event in Riga, Latvia, where he won the bronze medal.

Ranked first in both the short program and the free skate, he outscored the silver medalist, Japanese skater Yuma Kagiyama, by about 5 points.

[10] Qualifying to the 2019–20 Junior Grand Prix Final in Torino, Samsonov placed second in the short program despite falling on his opening triple Axel.

[12] Competing at the senior-level 2020 Russian Championships for the first time, Samsonov was seventh in the short program after stepping out of his quad Lutz and falling on his triple Axel.

[16] Samsonov missed the first half of the season due to treatment for Osgood-Schlatter disease, including time spent with a specialist in Germany.