Breitner's football career lasted from 1970 until 1983, mainly playing for Bayern Munich (1970–74 and 1978–83) and Real Madrid (1974–78), with one season playing for Eintracht Braunschweig. His early success was as a free roaming left back, as likely to score from the right midfield as to stop an attacker in his own penalty area. Later in his career he moved to midfield and became one of the top midfielders through the early 1980s.

During his club career, Breitner won seven National Championships with Bayern Munich (1972, 1973, 1974, 1980, 1981) and Real Madrid (1975, 1976), the Champions' Cup (1974) as well as the German (1971, 1982) and Spanish Cups (1975). During his spell with Bayern Munich, Karl-Heinz Rummenigge and he formed such a formidable one-two-punch that they were often called Breitnigge.

Breitner was an integral part of the West Germany team that won the 1974 FIFA World Cup, scoring in the final. He also scored in the final of the 1982 World Cup, making him one of only four players to have scored in two different World Cup final matches, the others being Pelé, Vavá and Zinedine Zidane.

Outside the pitch, Breitner was often decried by more traditional fans in Germany for his "revolutionary" attitude and his tendency for voicing strong opinions on political and social issues, especially during a time when Germany was still divided by the Berlin Wall. He was infamously seen bringing Mao Zedong's "little red book" to training. Before the 1982 World Cup held in Spain, he caused a major uproar in Germany when he accepted an offer by a German cosmetics company to pay him the – what many Germans regarded at that time as a "scandalously high" – sum of 150,000 Deutsche Mark if he shaved off his fluffy full beard, used their fragrance and advertised for the company. He further infuriated many fans with his move to Spanish giants Real Madrid, then associated with Caudillo General Franco. Breitner returned to Germany after a successful spell in Madrid and retired as a player in 1983.

In 1998, Breitner was announced as the new national coach by DFB President Egidius Braun. However, after some steam from fellow association officials, Braun reconsidered 17 hours later, making Breitner the infamous 17 Hours Bundestrainer.

One of the greatest German players of all time, Breitner was named in the FIFA World Cup All-Time Team, and was named by Pelé one of the top 125 greatest living footballers at a FIFA Awards ceremony in 2004. Breitner has been working as a commentator, pundit and columnist in Germany since retiring and is also an advisor to the Bayern management board.

Today, Breitner mainly works as a TV pundit and newspaper columnist. In March 2007 he entered into a contract with FC Bayern Munich and acts as an advisor on various issues. He occasionally still plays for the Bayern All-stars in charity games, captaining the team on several occasions.