[7] Making her ISU Junior Grand Prix debut, she won a bronze medal in Mexico[11] and finished seventh in Poland.

She competed at two ISU Challenger Series events, the 2014 Nebelhorn Trophy where she finished fifth,[14] and the 2014 Golden Spin of Zagreb where she placed eighth.

In 2015–16, Bell started her season on the ISU Challenger Series (CS), placing sixth at the 2015 U.S. International Classic and 13th at the 2015 Ondrej Nepela Trophy.

At the 2016 CS Ondrej Nepela Memorial, she placed fifth in the short, fourth in the free, and third overall behind Maria Sotskova and Yulia Lipnitskaya.

At the 2019 U.S. Championships, Bell underrotated the second part of her combination and placed third in the short program, behind Bradie Tennell and Alysa Liu.

[24] Lim's agency, All That Sports, stated to Agence-France Presse that the incident had been intentional and part of a pattern of bullying by Bell.

[26] Rafael Arutyunyan, who coached both Bell and Lim, denied the allegations: "The thing is that Mariah’s program includes an element where she lays her leg back and stretches it.

[30] Starting her season on the Challenger series at the 2019 CS Nebelhorn Trophy, Bell placed first in both segments to win the event, her first international gold medal.

[31] For her first Grand Prix assignment, Bell competed at the 2019 Internationaux de France, placing third in the short program with only an unclear edge warning on her triple flip.

[32] In the free skate, Bell underrotated a triple Lutz but otherwise landed all jumps cleanly and placed second in the segment, edging out reigning World and Olympic champion Alina Zagitova.

[38] After spending months off the ice in the midst of the pandemic, Bell resumed training in June 2020, stating that she hoped to use the time to work on developing a triple Axel, which she described as having "always been something that I believe that I can do.

For the short program, she recruited RuPaul's Drag Race contestant Cordero Zuckerman to work with Adam Rippon on a stylistic homage to vogue set to the music of Lady Gaga.

[48] Bell's two Grand Prix assignments were the final two events of the series, starting with the 2021 Internationaux de France, where she placed sixth.

[49] At her second event the following week, the 2021 Rostelecom Cup, Bell was third in the short program despite not landing a triple-triple combination, dropping to fourth after the free skate.

Bell won the short program, narrowly ahead of Karen Chen, while Alysa Liu was further back in third and withdrew before the free skate due to testing positive for COVID-19.

[53] Competing at the 2022 Winter Olympics in the women's event, Bell fell on her opening triple-triple combination attempt but nevertheless qualified for the free skate in eleventh position.

[55] Days after the Olympics concluded, Vladimir Putin ordered an invasion of Ukraine, as a result of which the International Skating Union banned all Russian and Belarusian skaters from competing at the 2022 World Championships.

This had a major impact on the women's field, dominated by Russians for most of the preceding eight years, and Bell entered the event as a podium contender.

[56] She finished third in the short program with a new personal best score of 72.55, taking a bronze small medal, the first for an American at the World Championships since Ashley Wagner in 2016.

[58][59] On October 12, 2022, Bell announced on Instagram that she was retiring from competitive figure skating and said she would continue performing at ice shows.

[60] She participated in the Japan Open later that fall, finishing sixth among the six female competitors and winning silver with Team North America.