To help channel the tireless energy of young Mahuchikh to good use, her sister brought her to the local sports club, where she trained, to try athletics next.

Under Stepanova's guidance, Mahuchikh deepened her love for sports and found her niche in high jump progressing rapidly in the next few years.

[19] In that year, Mahuchikh competed at international youth track and field competition between Ukrainian, Belarusian and Turkish national athletics teams in Lutsk, winning a silver medal.

[20] At the age of 15, Mahuchikh competed at her first international meeting in Minsk, jumping 1.82 m.[21] In May 2017, she won a first gold medal in her youth career at international youth track and field competition between Ukrainian, Belarusian and Turkish national athletics teams in Bursa with a clearance of 1.88 m.[22] In July 2017, she won the gold medal at the 2017 IAAF World U18 Championships in Nairobi by the largest margin in World U18 Championships history with a personal best and world age best of 1.92 m. She equalled the championship record of her compatriot Iryna Kovalenko from 2003.

[23] A few weeks later, she won the high jump event at the European Youth Olympic Festival in Győr with a clearance of 1.89 m.[24] In May 2018, Mahuchikh competed at the international meeting Internationales Pfingstsportfest, winning a bronze medal with a jump of 1.86 m.[25] In July 2018, Mahuchikh added 2 cm to her PB clearing 1.94 m at the European U18 Championships and won the gold medal by 10 cm over the runner-up, setting a new championship record.

[28] A month after her Youth Olympic success, Mahuchikh improved her personal best to 1.96 m and equaled the world U18 best in an annual indoor meeting in Minsk.

[31] On 30 June, at the Prefontaine Classic in Palo Alto, 7th leg of the 2019 Diamond League series, Mahuchikh cleared 2.0 m for the first time, becoming the youngest jumper in history to do so.

[41][42][43][44] In August, Mahuchikh won the 2020 Herculis in Monaco, the first leg of the delayed 2020 Diamond League series, which had to revise their schedule and format due to the COVID-19 pandemic.

[45] Five days later, she won the silver medal at the Irena Szewinska Memorial in Bydgoszcz, jumping 1.97 m.[46] On 23 August, Mahuchikh won the second Diamond League stage BAUHAUS-galan in Stockholm equalling the outdoor world-leading mark of 2.00 m set by her compatriot Yuliya Levchenko in July 2020 when she opened her outdoor season in Kyiv.

[64] In March, days after fleeing the Russian invasion, Mahuchikh claimed the gold medal in the high jump at the World Indoor Championships in Belgrade.

[67] In April, Mahuchikh won the Diamond League stage Prefontaine Classic in Eugene, jumping a world-leading mark of 2.00 m, to claim her first circuit victory since the start of Russian invasion of her country.

[71] In September, she won the high jump at the Brussels Diamond League meeting with a world-leading mark of 2.05 m, which was also a Ukrainian national record.

Both athletes were nominated for displaying "incredible strength and resilience" to win silver and bronze medals respectively at the Oregon 2022 World Championships, despite facing huge challenges due to the current situation in Ukraine.

[85] Three days later after Mahuchikh's win at the World Championships, Estonia handed over a lifesaving demining robot "Yaroslava", named after her, to the Ukrainian Armed Forces.

[93] In January, Mahuchikh kicked off her 2024 campaign at the Internationales Springer-Meeting in Cottbus in superb form clearing a world-leading jump of 2.04 m, both a meeting record and the highest she ever started in a competitive year.

[99] On 8 July, a day after Mahuchikh set the new world record, Russia launched a massive missile attack on Ukraine killing at least 47 people and injuring about 170 others including 2 adults who died when Okhmatdyt children's hospital was hit.

[113] In September, Mahuchikh won the Diamond League stage Weltklasse Zürich amid rainy conditions with a clearance of 1.96 m, her lowest winning height in a year and a half at international competitions.

[116][117] In October, Mahuchikh opined in an interview that Swedish pole vaulter Armand Duplantis is the best male athlete of the world because of his record breaking achievenents.

[125][126] Later in the month, a photograph capturing Mahuchikh kissing her gold medal at the 2024 Summer Olympics made it to finalist list of the 2025 World Sports Photography Awards under "Athletics" category.

[133] In February, she debuted her indoor season, finishing first at the International High Jump Meeting Udinjump, held in Udine, Italy, secondly since 2021, jumping 1.94 m, but with three failures at 1.98 m.[134] After the final event at the 2020 Summer Olympics, Mahuchikh congratulated Russian high jumper and Olympic champion Mariya Lasitskene for her win and hugged her.

[135] Her gesture of sportmanship however evoked a wave of nationalistic feelings among Ukrainians and caused a controversy because of the ongoing Russo-Ukrainian War and the fact that both athletes were honorary members of their respective country's armed forces.

[136] Ukrainian karateka Stanislav Horuna, who won bronze in the men's under 75 kg kumite karate category, took to Facebook to express his support for Mahuchikh.

In June 2023, at the Lausanne diamond league, after the IOC made a partial change of decision in March 2023 recommending international federations to allow the gradual return of neutral Russian athletes - those evaluated to have no military links - back to international competitions, Mahuchikh publicly criticised president of the IOC Thomas Bach arguing defending Russian athletes citing discrimination is unacceptable when Ukraine's situation remained unchanged and many of her country's athletes were still deprived of a safe and proper training facility.

But IOC's decision in March 2023 held off on deciding whether Russian and Belarusian athletes could compete at next year's Summer Olympics until an appropriate time.

For the sport of track and field, athletes from Russia and Belarus continued to be excluded from the Paris Summer Games according to its governing body.

[152] In August 2024, after her win at the 2024 Summer Olympics, Mahuchikh transferred a portion of her prize money to animal rights groups and military needs in her country.

[156] In October 2024, Mahuchikh told Tribuna, a Ukrainian sports publishing house, in an interview that she donated her 2024 Paris Olympics competition bib to the "Heroes Cup" charity auction where it was sold for 300,000 hryvnas (UAH) to help with military rebuilding effort.

[160] In November 2024, Mahuchikh told to a television host and media personality Masha Efrosynina in an interview that she privately donated to troops of the Ukrainian Armed Forces since the beginning of the Russian invasion in 2022.

[161][4] She is currently dating Nazar Stepanov, a Ukrainian hurdler and their national record holder, who is the son of Mahuchikh's coach Tetiana Stepanova.