Prince William's sister-in-law was the 412th out of 1,734 women contestants to finish the 90-kilometre race, clocking in at seven hours, 13 minutes and 36 seconds.
Pippa, an avid athlete, took part in Sweden's longest cross-country race, which runs from Sälen to Mora in the west near the border with Norway, to raise money for charity.
"It was incredible and it was faster than I thought I would manage," Pippa was quoted by the Swedish-language Aftonbladet daily as saying.
"Now I'm going to rest and put my feet up."
Pippa's brother James was 10 minutes behind Crown Prince Frederik of Denmark, who arrived 5,531th out of the 14,072 men in the race with a time of 6:36:32.
"To finish in about seven hours is a really good time," Vasaloppet spokesperson Per Strid said of Middleton's time to the TT news agency.
The winner of this year's race was Jorgen Brink for the second straight year, trimming 16 seconds off the course record with a time of 3:38:41.
The women's winner was Vibeke Skofterud of Norway with a time of 4:08:24.
Some 15,800 skiers started the race, inspired by a dramatic turning point in 1521 for Sweden's future king Gustav Vasa, who was locked in a life and death struggle against invading Danes.
The first race took place in 1922 and has been held nearly every year since.
Vasaloppet has a reputation as one of the great European events of the winter season, attracting increasing numbers of world class skiers.