In the 2012–13 season, Radionova made her ISU Junior Grand Prix debut and won her events in France and Austria.

She qualified for the JGP Final in Sochi, where she won the gold medal, finishing more than eleven points ahead of silver medalist, Hannah Miller, from the United States.

[14][15] At the 2013 Russian Championships, Radionova won the silver medal in the senior event ahead of defending champion Adelina Sotnikova and then took the junior title.

She was awarded the gold medal while defending champion Yulia Lipnitskaya took silver and Anna Pogorilaya the bronze — resulting in a Russian sweep of the podium.

Placing first in both programs, she won the gold medal by a margin of more than 25 points over two-time world champion Miki Ando from Japan.

Scoring 66.90 points in the short program, 127.39 in the free skate, and 194.29 for the combined total, she broke junior-level ladies' records previously held by Mirai Nagasu and Yulia Lipnitskaya.

[19] Radionova, Serafima Sakhanovich, and Evgenia Medvedeva produced Russia's second consecutive sweep of the World Junior ladies' podium.

During the off-season, Radionova performed in various Russian cities with Show of the Champions and in Korea with Igor Bobrin's Theatre on Ice.

[20] Radionova made her season debut at the 2014 Japan Open where she placed first in the ladies' free skate and helped Team Europe win the gold medal.

Although a fever prior to the event reduced her training time,[24] she took the silver medal in Barcelona, finishing behind teammate Elizaveta Tuktamysheva.

[26] Although she was not fully recovered from a high fever and virus, she insisted on competing at her first Grand Prix event of the season, the 2015 Cup of China; she won the bronze medal behind Mao Asada and Rika Hongo.

At the 2015 Rostelecom Cup, held in late November in Moscow, she won the gold medal ahead of teammates Evgenia Medvedeva and Adelina Sotnikova.

She repeated as the European silver medalist while her teammates completed the podium, with Medvedeva winning the gold and Anna Pogorilaya taking the bronze.

Radionova's Grand Prix assignments for the 2016–17 season, her first event was at the 2016 Rostelecom Cup where she finished second in both the short and free skating, winning the silver medal overall behind teammate Anna Pogorilaya.

Then in her next event at the 2016 Cup of China, Radionova finished second at the short program and won the free skating, winning the gold medal with a total of 205.90 points qualifying to her fourth consecutive Grand Prix Final, to be held in December in Marseilles, France.