Valary Jemeli Aiyabei was born on 8 June 1991 in Kenya. She came to athletics late, training alone in Iten after an early adulthood that included selling vegetables to get by. She ran her first serious marathon in 2013 and improved steadily over the following years without a named coach or formal training group.
She set Spanish all-comers records at the 2016 Barcelona Marathon (2:25:26) and Valencia Marathon (2:24:48) in the same calendar year. In 2017 she won the Prague Marathon in a course record, and in 2018 she became the first Kenyan woman to win the Beijing Marathon, a World Athletics Gold Label event, finishing in 2:21:38.
Her best performance came at the 2019 Frankfurt Marathon, where she won in 2:19:10, becoming the first woman to run sub-2:20 at that race. At the time she ranked among the 12 fastest women in marathon history. Her half marathon personal best of 1:06:14, set at the Ras Al Khaimah Half Marathon in February 2019, confirmed her speed at the shorter distance. She continued competing into her mid-thirties, winning the California International Marathon in December 2025 at age 34.