[2] Their Finnish parents – Hanna, a former figure skater, and Ville Peltonen, a former ice hockey player – had moved to the United States due to his contract with the NHL's Nashville Predators franchise.

Making her senior international debut, Peltonen placed tenth at the Finlandia Trophy, a Challenger Series (CS) event in October 2015.

In December 2016, Peltonen won the senior gold medal at the Finnish Championships in Tampere,[5] having outscored silver medalist Jenni Saarinen by eight points.

Peltonen competed at the 2017 World Championships in Helsinki, Finland, but did not advance to the free skate, having placed twenty-ninth in the short program.

In September 2017, Finland qualified a spot in the ladies event at the 2018 Winter Olympics due to Viveca Lindfors' result at the 2017 CS Nebelhorn Trophy.

In December, Peltonen won her second consecutive national title, finishing ahead of silver medalist Lindfors by a margin of 4.22 points.

In January, Peltonen placed eleventh in the short program, eighth in the free skate, and ninth overall at the 2018 European Championships in Moscow, Russia; she was Finland's top lady at the event, finishing 11 points ahead of Lindfors.

[7] Peltonen began the new season at the 2018 CS Finlandia Trophy on home soil, finishing in fifth place, two ordinals below Lindfors, who won the bronze medal.

[8] Based on the season's results, the Finnish Federation assigned Lindfors to Finland's lone ladies' spot at the 2019 World Championships.

[14] After contracting COVID-19, she was forced to withdraw from her other planned fall assignments, including the special home 2022 Grand Prix of Espoo.

She would subsequently compete at the 2023 Trophée Métropole Nice Côte d'Azur, where she won the gold medal before going on to finish eighth at the 2023 CS Warsaw Cup.