[4] Harrington studied international affairs with an emphasis on politics in Sub-Saharan Africa at the University of Colorado at Boulder.

[1] In 2012, Harrington was asked to join a joint expedition with The North Face and National Geographic to climb Mount Everest.

This peak had only been climbed once before and Harrington's team intended to create their own route rather than follow that of the previous expedition.

[4] In November 2020, Harrington became the fourth woman (after Lynn Hill, Steph Davis, and Mayan Smith-Gobat) to free-climb the 3,000 ft (910 m) granite wall of El Capitan (which she did via Golden Gate), in a single day.

The year before, while practicing the El Capitan climb, an accidental 50 ft fall required her to be rescued.

[15] In 2021, Harrington achieved the first individual free climb of The American Way route on Pik Slesova in Kyrgyzstan.

"[16] However, they repeated a free route previously established by the team of Nik Berry, Eric Bissel, Brent Barghan and Dave Allfrey in August 2019.