Playing career

Leonardo began his career with the Brazilian club Flamengo in 1987; at just 17, he was given the opportunity to play with his hero Zico plus Leandro, Bebeto and Renato Gaúcho, and to take part in winning his first Brazilian championship. In 1990, Leonardo signed with São Paulo FC, and in 1991, Leonardo, Raí, and other young talents were assembled as part of the so-called "esquadrão tricolor" under the command of Brazilian legend Telê Santana, giving Leonardo his second Brazilian championship.

Later that year, he made the switch to European football, signing with the Spanish club Valencia CF. After two seasons with Valencia, he returned to Brazil for a brief stint with São Paulo in 1993, during which time the team won several titles, including the prestigious Copa Libertadores and Toyota Cup.

Leonardo made his international debut in 1990. He was selected as a leftback for the 1994 World Cup, keeping the young Roberto Carlos out of the team, much to his chagrin. Leonardo played well in the first games but was then given a four match suspension for elbowing the American midfielder Tab Ramos, resulting in a broken Malar bone. Leonardo personally apologized to Ramos, claiming the vicious blow was unintentional. His suspension prevented him from playing the rest of the games of the World Cup. It was the second longest ban imposed in World Cup history.

In 1994, after the World Cup, Leonardo signed with the Kashima Antlers of the newly-formed J. League. Leonardo continued his success in Kashima, again playing with his idol and friend Zico. In 1996, he returned to Europe, this time signing with French club Paris St Germain, where he again proved to be successful, one of his goals helping them to oust Liverpool FC out of the semi-finals of the UEFA Cup Winners' Cup.

At this point in his career, Leonardo had mostly stopped playing as a leftback and moved into the midfield, sometimes on the left, sometimes as a playmaker. Already in Japan, this had resulted in some spectacular goals for Leonardo, a trend which continued in Europe.

In 1997, Leonardo was given the #10 shirt for the national team. He was an important member of the team that won the Copa America in 1997. In the summer of 1997 he signed with Italian team AC Milan, for 8.5 million euros from Paris St Germain. With Milan he became a prominent part of a star-studded lineup. He played four full seasons, scoring 22 goals and playing 177 games for Milan, placing himself amongst the greatest Rossoneri legends of all time, before returning to Brazil with São Paulo FC and Flamengo. He later returned to AC Milan and finished his career with them in 2003.

Leonardo played all seven games in his second 1998 FIFA World Cup, helping Brazil to a second-place finish. In the second opening round match against Morocco, he netted one shot and began celebrating, but was later called off-side. He was last selected to play for Brazil in the 2002 FIFA World Cup qualifying campaign and ended his career with 60 caps and 18 goals for Brazil.

Post-playing career

Since 2002, Leonardo has dedicated himself to social works with the Fundação Gol de Letra and Fondazione Milan.

Leonardo worked for BBC Television in the United Kingdom during the 2006 FIFA World Cup, as one of their Match of the Day analysts, alongside another former World Cup winner Marcel Desailly. He appeared again as a Match of the Day analyst on 1 June 2007 alongside Alan Hansen and Alan Shearer. This was the first England game at the new Wembley Stadium finishing 1-1 with Brazil.

Since Leonardo stopped playing for Milan he has become a sort of combination of scout and agent for the club in Brazil and the great respect he enjoys in his homeland has helped Milan to land several world-class players. He was instrumental in the process of getting Kaká to Milan and in July 2007 it was revealed that Leonardo had been one of the main factors in convincing Alexandre Pato to sign for Milan.

Coaching career

In December 2007, he was interviewed for the vacant position of director of football at English premiership side, West Ham United.

In early 2008 he was appointed Technical Director of his former club AC Milan. Later the same year he obtained Italian citizenship, after twelve years in Italy as a resident.

After Carlo Ancelotti left AC Milan to become the manager of Chelsea FC at the end of May 2009, Leonardo was named head coach of Milan.

Leonardo wasted no time in declaring that he wanted his team to play attractive attacking football, even invoking the name of his old mentor, Telê Santana