A professional footballer from Argentina, Sebastian Ariel Romero began his professional career at Gimnasia La Plata in 1996. In his three year tenure, he played for the team 80 times, scoring 12 goals in three seasons. His performances brought him to Real Betis for one season, where he played 23 games. He went to Toulouse FC in 2001 but only saw action in 7 games, scoring once.
The later half of 2001, and part of 2002, he came back to Argentina and played for Cordoba CF. At the end of 2002, Romero moved to Racing club for a four season long tenure and played over 110 games for the team, scoring 14 times. In 2006, Romero moved to Greece and to giants Panathinaikos for 36 matches that saw 4 goals being scored. At the beginning of 2008, Romero was back in Argentina, to play with Gimnasia La Plata in the Primera Division.