She attended Princeton University where she studied ocean health and was influenced by ethicist Peter Singer.
After her fellowship ended Gallagher moved to Boulder, Colorado and became active in the local trail running community.
She won Western States in 2019 shortly after going on a two-week mountaineering expedition in the Arctic National Wildlife Refuge to advocate for the ANWR.
[6][1][10] Gallagher won the Best of the Rockies—Advocate award from Elevation Outdoors Magazine in 2020 for her work as a Patagonia ambassador and POW athlete.
The magazine noted that "she is a constant voice for climate action, social justice, and public lands.