Caldwell took part until 2012 mainly in competitions of the US Super Tour and the Nor-Am Cup. At the US cross-country skiing championships in Rumford in 2011 , she won silver in the sprint. She ran her first World Cup race in December 2012 in Québec , which she finished with 14th place in the sprint and thus got her first World Cup points. At the US cross-country skiing championships in 2013 in Midway , she won silver in the sprint and bronze over 20 km classic. At the Nordic World Ski Championships in 2013 in Val di Fiemme , she finished 20th in the sprint. In the 2013/14 World Cup season she achieved her first top ten placement in the World Cup with ninth place in Davos . At the 2014 Winter Olympics in Sochi , she finished sixth in the sprint and seventh in the team sprint. In March 2014 she was able to achieve her first podium in the World Cup with third place in the sprint competition in Lahti . She finished the World Cup season in 23rd place in the overall standings and in eighth place in the sprint standings. At the Nordic World Ski Championships in Falun in 2015 , she finished tenth in the sprint and eighth in the team sprint. After two top ten placements at the beginning of the 2015/16 season at sprint world cups in Davos and Toblach , she won her first World Cup victory in the 2016 Tour de Ski , which she ended prematurely, in the sprint in Oberstdorf. In January 2016 she came back on the podium with second place with the relay at the World Cup in Nové Město . Her best placement at the Ski Tour Canada , which she ended prematurely, was tenth place in the sprint stage in Québec . She finished the season in 27th place in the overall World Cup and seventh in the Sprint World Cup. In the summer of 2016, she took third place in the Australia / New Zealand Cup in Snow Farm in the sprint and 10 km mass start race. In the 2016/17 World Cup season, she finished in the top ten three times in the individual sprint. In January 2017 she won the sprint at the Alpencup in Planica . The following month, she and Ida Sargent took third place in the team sprint at the World Cup in Pyeongchang . At the season highlight of the Nordic World Ski Championships 2017 in Lahti, she was sixth in the sprint. At the end of the season she came in 36th place in the overall ranking at the World Cup finals in Québec and reached 33rd place in the overall World Cup and 11th place in the Sprint World Cup. After 39th place in the Ruka Triple at the beginning of the 2017/18 season, she finished second in the sprint at the Tour de Ski stage in Lenzerheide . Third places in the sprint and team sprint in Dresden and a victory in the sprint in Seefeld in Tyrol followed . At the 2018 Winter Olympics in Pyeongchang, she was eighth in the sprint and fifth in the relay. At the end of the season she achieved 36th place at the World Cup finals in Falun and finally reached 19th place in the overall World Cup and third place in the Sprint World Cup.
In the 2018/19 season, Caldwell came six times in the World Cup sprint in the top ten, including three times in second place and thus achieved 21st place in the overall World Cup and fourth place in the Sprint World Cup. At the end of January 2019, she won the sprint of the US Super Tour in Lake Placid and finished second in the 5 km freestyle. At the season highlight, the Nordic World Ski Championships 2019 in Seefeld in Tyrol , she ran on 29th place over 10 km classic and 14th place in the sprint. At the beginning of the 2019/20 season, she came third in the sprint in Davos and second in the relay in Lillehammer . This was followed by four top ten placements in the sprint and 44th place in the ski tour. She achieved sixth place in the Sprint World Cup.