During a 16-year professional career, he amassed Eredivisie totals of 348 games and 146 goals, mainly in representation of Den Bosch and PSV, also playing abroad in Scotland, Japan and Finland.

In the 1987 summer, A.C. Milan bought Ruud Gullit from PSV Eindhoven for a world-record transfer fee £6,000,000, and that money was soon used in the acquisition of Gillhaus, Wim Kieft and Søren Lerby.

The former netted 15 goals in only 26 games in his first season, helping the Philips club to a historic treble – he appeared 105 minutes in the campaign's European Cup final, a 0–0 penalty shootout win against S.L.

[2] While with Aberdeen, Gillhaus collected a Scottish Cup winners medal in 1989–90, scoring twice en route to the final against Celtic and starting in decisive match, another penalty shootout triumph.

Gillhaus made his debut for Netherlands on 28 October 1987, in a UEFA Euro 1988 qualifier against Cyprus in Rotterdam (8–0 win), a game marred by the "bomb incident".