Halfvarsson advanced from the qualifying round of the classic sprint in 26th place. He then advanced to the quarterfinals after finishing fifth in his heat.
The competition was Halfvarsson's first in several weeks after the 36-year-old missed the Scandinavian Cup in Östersund because of a lingering cold.
"It's been a while since I competed, so it'll be exciting to see how the body responds. You don't know anything now, after all. You just have to go there and hope for the best," Halfvarsson told Falu-Kuriren before his return.
Halfvarsson is outside the national team and is training independently, focusing on sprinting.
During the Swedish season opener in Gällivare in November, Halfvarsson had poor results and has not competed in the World Cup this season.
To have a chance at an Olympic spot, Halfvarsson needs to perform in this weekend's Scandinavian Cup distance race to qualify for the World Cup and be able to fight for the final spots.
National team riders Marcus Grate and Oskar Svensson did not advance from the sprint prologue. Emil Danielsson, like Halfvarsson, made it to the quarterfinals.
