His 17-year professional career was mainly associated with Brøndby IF, for which he played in 470 official games – being the club's top scorer in history – and won ten major titles.

After spending the 1985–86 campaign in France with Lille OSC – only one Ligue 1 goal, club finished in tenth position – Vilfort returned to his country and signed for defending champions Brøndby IF, where he would play out the rest of his career as an attacking midfielder; in the 1986–87 European Cup, the first-ever European competition participation for the team, he scored two goals to help them reach the third round.

[1] Vilfort made his debut for the Denmark national team on 5 October 1983, in a 1–0 defeat against Poland for the 1984 Summer Olympics qualification.

In the Euro 1992 tournament in Sweden, Vilfort was a nuclear unit for the Danes, being one of the few offensive players in the team's otherwise defensive strategy.

He played four of five matches in the competition, having to leave training camp to visit his leukemia-stricken 7-year-old daughter whose condition was deteriorating, thus missing the group stage decider against France (2–1 win).