De Keyzer's freelance career began in 1982, at which time he also taught at the Royal Academy of Fine Arts, Ghent, Belgium. During this time, he co-founded the XYZ-Photography Gallery. He has exhibited his work in many European galleries and has received several awards, including the Book Award from the Arles Festival, the W. Eugene Smith Award (1990) and the Kodak Award (1992). Major subjects in his worked have included the collapse of Soviet Union and India. Robert Koch gallery describes his work as investigating "marginalized social groups and constructs uncritical psychological portraits which work to familiarize the 'other.'" He currently lives in Ghent and continues to teach.
He was nominated to the Magnum Photos agency in 1990, became an associated member in 1992 and a full member in 1994.