[6][7] She was born with cerebral palsy (spastic diplegia) and developed generalised dystonia, a progressive neurological movement disorder, in her mid teens.

[10] She attended The Cooper and Jordan School in Aldridge, where one of her fellow pupils was future Paralympic gold medallist Ellie Simmonds.

[13][14] She began a Master's degree course in Human Physiology at her alma mater, but had to give this up after a head injury in 2023 resulted in post-concussion syndrome and a deterioration of her dystonia.

[15] Kearney began swimming at the age of eight after being approached by a coach while she watched her older brother train at a local club.

[7] The 2011/12 season saw Kearney selected as a World Class Development Funded Athlete by British Disability Swimming, under the coaching of Nathan Hilton.

[18] Her performance on that day earned her a place on the British team competing at the 2013 IPC Swimming World Championships in Montreal.

[18] Kearney entered five different events at the World Championships and won bronze in the women's 400 m Freestyle S10 behind France's Elodie Lorandi and Canada's Aurelie Rivard.

[6][19] An illness during the British national trials in 2014 resulted in Kearney missing out on places at both the Commonwealth Games in Glasgow and the European Championships in Eindhoven.

[20] Her first event back in the pool, having recovered from her illness, was as part of National Paralympic Day at the London Aquatics Centre, where she won the multi-classification 400m freestyle.

[10] She returned to the pool in 2017 and was reclassified as a S7, SB6 and SM7 swimmer at the British Para Swimming International Meet in April of that year due to the further progression of her disability.

She has shared that this "incredible experience" gave her "massive appreciation for all the volunteers" who are essential in ensuring that large-scale sports events can go ahead.

[37] Kearney was forced to withdraw from the 2023 World Championships due to a significant head injury which resulted in post-concussion syndrome.

[citation needed] The injury also triggered a further deterioration of her dystonia, particularly affecting her left arm, hand and wrist, as well as her shoulders and legs.

Kearney has spoken about the impact that the head injury has had on her life, both physically and mentally; not only did it disrupt her swimming career, but the effects on her memory, vestibular system and eye tracking resulted in her having to withdraw from her Master's degree course.