In 2015, Grace Zimmerman competed in the Miss Tri-Counties Outstanding Teen 2015 pageant. She later went on to compete for and win Miss Three Rivers Outstanding Teen 2015. She went on to compete for Miss Idaho's Outstanding Teen 2015 and placed fourth runner-up.
On June 8, 2019, she competed at the Miss Idaho 2019 competition where she walked away as first runner-up to Miss Idaho 2019.
On Wednesday, June 12, 2019, the Miss Idaho Scholarship Organization announced that Miss Idaho 2019 Rachel Forest stepped down from her newly won crown. First runner-up, Grace Zimmerman ascended to the title becoming Miss Idaho 2019 and winning the opportunity to represent Idaho at Miss America 2020.
Upon hearing the news, Zimmerman said, "To say I'm feeling blessed would be an understatement. After spending the past week competing alongside some of the most charismatic, driven, and talented young women, I walked away feeling more proud than ever of this organization and the way it shapes women into stronger versions of themselves. As Miss Idaho, I am thrilled at the opportunity to represent my fellow candidates, our Miss Idaho Organization, and the state of Idaho."