Fiona O'Keeffe won 2014 Gatorade California Cross Country Runner of the Year.

[4] She also ran 15:56.84 for 5000 metres at the 2016 USATF U20 Outdoor Championships, making her the 6th-fastest US high school performer of all time.

[8] In June of the same year, she ran a 5000 m personal best of 15:05.56 in Portland and placed sixth in the 5000 m at the USA Track and Field Championships.

In 2023, she ran personal bests over 5000 m (15:01.34) and 10,000 m (30:52.77), and represented the United States in the 5 km at the World Road Running Championships, placing sixth.

[1] She competed in the 2024 Paris Olympics Women's marathon on 11 August 2024 where she dropped out before 5k due to hip injury and did not finish.