Nicknamed El Conejito (The Rabbit), Saviola made his debut for Argentine side River Plate at the age of 16, and went on to be a prolific goalscorer for the club. He helped River Plate win the 1999 Apertura and 2000 Clausura championships, and earned the 1999 South American Footballer of the Year award. Still only 18, he gained a reputation as a phenomenal prospect.

Saviola starred in the 2001 edition of the World Youth Cup, held in Argentina. He was top scorer and was voted player of the tournament, as the Argentine youth national team won the competition. With 11 goals in seven games, he became the record goal-scorer in World Youth Cup history.

That summer, aged 19, he moved abroad to play for FC Barcelona in Spain. He obtained Spanish citizenship, and thereby wasn't restricted by the Spanish league maximum on the number of non-European Union citizens allowed in each club. Under coach Louis Van Gaal, he scored 17 goals in his first season, finishing third best scorer in La Liga.

Saviola with BarcelonaHis second year at the club did not start well, as he only scored two goals in the first half of the season. When Van Gaal was fired and Radomir Antić became new Barcelona manager, Saviola went on to score eleven goals in the latter half of the 2002-03 season. At the start of the 2003-04 season, Frank Rijkaard was appointed as new manager. Saviola scored 14 goals during the season, but was deemed surplus at the club.

Saviola played in the 2004 Olympic Games and won the Olympic Gold Medal with the Argentine squad. Under coach Marcelo Bielsa, Saviola had few playing opportunities for Argentina, but after Bielsa's resignation in 2004, new coach José Pekerman gave Saviola more playing time.

Saviola was sent on loan the following year, as he moved to AS Monaco in the French Ligue 1 championship in the summer 2004. As he did not fit into Rijkaard's plans, Saviola was again loaned out in the summer of 2005, this time to Spanish club Sevilla FC, in order to replace attacking player Júlio Baptista who moved to Real Madrid. At Sevilla, Saviola won his first title in Europe, when the club won the 2006 UEFA Cup.

Saviola was called up to represent Argentina at the 2006 FIFA World Cup by José Pekerman. Striker Luciano Figueroa and winger Luciano Galletti were in contention for a place on the roster, but Saviola's excellent form for Sevilla, scoring a handy 20 goals in 55 games and winning UEFA Cup with the Andalusian team, secured his place in the squad. Saviola made his presence felt at the tournament, as he scored a goal against Côte d'Ivoire in Argentina's opening game, and made two assists in the 6-0 victory against Serbia and Montenegro.

Saviola returned to Barcelona for the 2006/07 La Liga season, playing in 18 league games (6 as a starter, 12 as a substitute) and scoring 5 goals. In the Copa del Rey, he appeared in 5 games (3 starts, 2 substitutions), scoring 5 goals. He also made a solitary Champions League appearance, but did not score.

On July 10, 2007 it was reported that Real Madrid signed Javier Saviola after he was released by Barcelona. The Club's website published Saviola's first interview in Madrid on July 12, confirming that he would be presented to the press the next day as a new Real Madrid player. On July 13 Saviola completed his free transfer to Real Madrid CF, signing a contract that ends in 2011.

On August 03 2007, Saviola scored his first goal for Real Madrid against FC Lokomotiv Moscow. Also, He scored his second goal for Real Madrid against PSV Eindhoven two days later on August 05 2007.