Before joining Telstar, he played for amateur football clubs DSS and Onze Gezellen.

Geels scored 46 goals in 89 league games for Feyenoord, but also faced competition for the striker position with Swede Ove Kindvall.

In 1970, Geels left Feyenoord for Go Ahead Eagles, where he played for two seasons, scoring 35 goals.

Geels returned to Belgium in 1978 to play for Anderlecht, where he won the 1978 UEFA Super Cup against Liverpool.

He returned to the Netherlands in 1979 to play for Sparta Rotterdam, scoring 35 goals in two seasons, while also becoming for the fifth time the best Eredivisie top scorer in 1980-81.

Geels died in 18 November 2023, at the age of 75, having suffered from Alzheimer's disease for a long time.