Pål Haugen Lillefosse gained his first international experience in 2017 when he won the gold medal at the European Youth Olympic Festival (EYOF) in Győr with a skipped 5.00 m and competed with the Norwegian 4 x 100 meter relay in 41.79 s won the silver medal. In the following year he won the U18 European Championships there with a new championship record of 5.46 m and won the bronze medal in the 100-meter run in 10.72 s and was eliminated in the sprint relay (1000 meters) with 1: 59.58 min in advance. In 2019 he won the U20 European Championships in Borås, Sweden, with 5.41 m.
In 2019 and 2020 he became Norwegian indoor pole vault champion.
Personal best
100 meters: 10.55 s (+1.5 m / s), June 7, 2018 in Oslo
60 meters (hall): 6.91 s, March 10, 2018 in Steinkjer