Diggins has used her status as a famous athlete to advance advocacy related to climate change and eating disorders.

In 2008, Diggins was the top-ranked girls' individual cross-country skier in the Minnesota high school rankings.

[12] She fell out of the Minnesota high school rankings in 2009 when she competed and won the United States Junior National Sprint title on March 9 of that year.

[14] Diggins earned an academic scholarship to Northern Michigan University but deferred enrollment to race with the Central Cross-Country Elite team for one year.

[5] Diggins won a gold medal with Kikkan Randall in the team sprint in the 2013 FIS Nordic World Ski Championships in Val di Fiemme.

[16] Diggins won the silver medal in the 10-kilometer freestyle race in the 2015 FIS Nordic World Ski Championships in Falun.

[17] At the 2017 Nordic World Ski Championships in Lahti, Finland, Diggins took two medals: in the freestyle sprint, she won her quarterfinal and semifinal heats on her way to taking the silver, ahead of teammate Randall in third.

Schlanger: Jessie Diggins with two fifth-place finishes, one-sixth, so close for the U.S. on so many occasions, now moving up on the outside into second place!

Schlanger: As the roars rattle around the cross-country stadium in Pyeongchang, Sweden, the U.S. and Norway coming to the line!

She placed atop the overall World Cup 2020–2021 season standings, claiming the biggest annual prize in cross-country skiing.

[29] At the FIS Nordic World Ski Championships 2023 in Slovenia, Diggins and teammate Julie Kern won bronze in the team sprint.

Two days later, Diggins won gold in the 10 km freestyle, which was the first top medal for an American in an individual event at any cross-country skiing world championship.

While on break from the World Cup ski tour mid season, Diggins competed in the American Birkebeiner in Wisconsin, and won the 50 km freestyle race on February 24, 2024.

Poplawski, a native of Winnepeg, Manitoba, Canada, is a former minor league hockey player for the Rapid City Rush.

[35] Diggins is an ambassador for the non-profit organization Fast and Female, which inspires girls ages 8–18 to be active and empowered in sports.

[36][37] Diggins is also an ambassador for the non-profit organization Protect Our Winters (POW), whose aim is to effect systemic solutions to climate change through the outdoor sports community.

In several interviews and essays, she revealed her experience of seeking treatment for bulimia at the organization in 2010, with the aim of using her story to help improve self-acceptance and reduce stigma and secrecy around eating disorders for others.

[38][39] In 2020, Diggins wrote an autobiography, Brave Enough, about her athletic accomplishments and personal struggles with bulimia as a teenager.