On 29 October 2004, he signed his first professional three-year contract with Feyenoord, at the age of 16. However, later that year, Biseswar was suspended by the KNVB for a month after he "played in a competition match, under a different name, in the first team of an amateur club from Amsterdam but was quickly picked out during the game as player of Feyenoord." On 22 May 2005, Biseswar made his senior Feyenoord debut by replacing Tim Vincken in the 67th minute in Feyenoord's last Eredivisie match of the 2004–05 season. Feyenoord defeated ADO Den Haag (6–3), which was also the last match under the management of Ruud Gullit.