Song started his professional career with Metz and helped the club to win the Coupe de la Ligue in 1996. After appearing at the 1998 World Cup, he joined Salernitana, newly promoted to the top-flight Italian Serie A. In January 1999, he left Italy to start successive stints with Liverpool, West Ham United and 1. FC Köln, but after failing to hold down a first-team place, he returned to France to play for Lens. He stayed there until 2004 and moved on to Turkey, where he spent four years with Galatasaray, winning two Süper Lig titles and the Turkish Cup. Song then signed a contract with Trabzonspor in 2008, where he won another Turkish Cup and stayed until 2010.