After college, Grabill quickly moved up to the half marathon distance. She placed second at the 2018 Indianapolis Monumental Half Marathon in a time of 1:13:21, which qualified her for the
2020 United States Olympic Trials (marathon). In 2019, she finished sixth at
Grandma's Marathon with a time of 2:35:11. In the fall, she won the Indianapolis Monumental Half Marathon in 1:12:20. At the 2020 Olympic Trials Marathon in Atlanta, Grabill placed 25th of nearly 400 women in a time of 2:37:57. At the
2024 United States Olympic Trials (marathon) in Orlando, Grabill placed 13th of 137 women in a time of 2:30:16. In December 2024, she logged her fastest marathon in Valencia with a time of 2:26:46. Grabill was the runner-up at the 2025 Marathon Project event in Arizona with a 2:28:56 time. ==Personal==