Maldini made his league debut in the 1984–85 season on 20 January 1985, replacing the injured Sergio Battistini in a match against Udinese at the age of 16. It was his only league appearance of the campaign, but he was in the starting eleven the following season. The 1987–88 Scudetto marked Maldini's first trophy, and the first of seven league titles, with the club. He was also part of Milan's undefeated Serie A champion side in the 1991–92 season. The back four that included Maldini and fellow long-timers Franco Baresi, Alessandro Costacurta and Mauro Tassotti is widely considered one of European football's most formidable defensive quartets of the 1990s. Following Baresi's retirement, he would also form a formidable and successful partnership with Alessandro Nesta.
In addition to winning his third Champions League and reaching the 1994 World Cup final, Maldini became the first defender ever to win World Soccer magazine's annual World Player of the Year Award. During his acceptance speech, Maldini called his milestone "a particular matter of pride because defenders generally receive so much less attention from fans and the media than goalscorers. We are more in the engine room rather than taking the glory."He then singled out Milan captain Franco Baresi as a player who "really [deserved] to receive the sort of award I have received."
Maldini played his 600th Serie A match on 13 May 2007 in a 1–1 draw at Catania. On 25 September 2005, Maldini broke Dino Zoff's Serie A appearance record after playing his 571st league match against Treviso; seven days earlier, he had played his 800th game in all competitions for Milan. On 16 February 2008, Maldini reached 1,000 senior games with Milan and Italy when he entered as a substitute against Parma.
Maldini has participated in eight UEFA Champions League finals during the course of his career, which is bettered only by Francisco Gento, who also appeared in a Cup Winners' Cup final, bringing his total European finals to nine. Maldini has lifted the trophy five times, the latest coming in Milan's 2–1 victory over Liverpool in the 2007 Champions League final on 23 May 2007 in Athens. In an interview with ESPN that aired prior to the broadcast of the 2007 final, he labeled the 2005 Champions League final, a match that Milan lost on penalties to Liverpool after blowing a 3–0 half-time lead, the worst moment of his career, even though he had scored the fastest-ever goal in a European Clubs' Cup final just 51 seconds into the match, in the process also becoming the oldest player ever to score in a final.
Maldini announced his plans to retire at the end of the 2007–08 season, saying that he would do so with "no regrets."However, following Milan's elimination from the Champions League by Arsenal in March, Maldini stated that he would possibly delay his retirement for at least a further year. He signed an extension on June 6 that kept him at Milan for the 2008–09 season On 18 April 2009, Maldini announced that he will be finally retiring at the end of the 2008–09 season.
On 17 May, in the Friuli Stadium, Maldini played his 900th official match for Milan in a league game against Udinese. Maldini's last match in San Siro was on 24 May, in a game lost 3–2 against Roma. There was a small controversy when the Milan fans known as "Brigate Rossonere" protested against Maldini as he said goodbye. His last appearance for Milan, and his last game as an active player was on 31 May 2009, in the last match of the season, against Fiorentina, which Milan won 2–0. Milan retired his number 3 shirt, but it will be bequeathed to one of his sons if one makes the club's senior side.
International career
In 1986, Maldini was called up by his father Cesare to the Italian U-21 side, where he earned twelve caps and scored five goals in two years. He made his Azzurri debut at the age of nineteen on 31 March 1988, in a 1–1 friendly draw against Yugoslavia, and made one appearance for Italy at the 1988 Olympics. Maldini featured in all four of Italy's games at Euro 1988, and participated in his first World Cup in 1990, where Italy lost to Argentina in the semifinals on penalties.
Maldini's first international goal came in his 44th career match, in a 2–0 friendly win over Mexico on 20 January 1993. He captained Italy at the start of the 1994 World Cup, losing to Brazil in the final on penalties. He was named in the Team of the Tournament, 32 years after his father received the same honour at the 1962 World Cup. Euro 1996 would see Italy eliminated in the group stage, and the quarterfinals of the 1998 World Cup. Italy did reach the final of Euro 2000, but lost to France in extra time.
After Italy were eliminated in the 2002 World Cup round of sixteen, Maldini retired trophyless from international competition as Italy's most capped player. He scored seven international goals, all coming in home games. He spent over half of his 16 years as an international as team captain, wearing the armband a record 74 times.
In February 2009, Italian head coach Marcello Lippi declared his support for a testimonial match for Maldini, stating that it would give him a chance to play for the Azzurri for a final time.Italian Football Federation offered him a place in the line-up in a friendly match against Northern Ireland. However, Maldini rejected the offer, saying that he wanted to part with football in an "official" match.
Retirement
Prior to his retirement, Maldini expressed that he would never be moving into a coaching career. He was offered a position that would have reunited him with his former manager, Carlo Ancelotti, by joining Chelsea as a coach having reportedly met with Ancelotti and with Chelsea's owner, Roman Abramovich, to discuss such a possibility. On 30 June 2009, Ancelotti announced that Maldini had turned down his offer to become part of Chelsea's coaching staff.
