O'Shea recorded her first World Cup podium with a silver at La Plagne in 2011, but spent the following two seasons on the lower-level tours. Returning to World Cup competition in 2014–15, she had a disappointing season with her best results being two ninth-place finishes and an 18th at the World Championships. In the 2015–16 season, however, she earned her first gold medal, at her home track in Lake Placid, along with a silver at Whistler and a fifth-place performance in the 2016 World Championships at Igls — finishing the season's overall World Cup rankings in fourth place, her best ever. She did not return to the same form for the 2016–17 season, however, with two sixth-place finishes as her best results and a 19th-place finish at the World Championships.