Pfaff was born in Lebbeke. At the age of 16, he joined K.S.K. Beveren with whom he won a Belgian champions title (1979) and a Belgian Cup (1978). The same year, he received the Belgian Golden Shoe. In 1982, he entered the Bayern Munich squad,[3] getting three Bundesliga titles (from 1985 to 1987) and two German cups (1984 and 1986).[4]
Despite his sturdy physical build, Pfaff possessed quick reflexes and was known for his spectacular playing style, as well as his ability to produce acrobatic saves, which made him an effective shot-stopper. He was also known for his extroverted and outspoken character, his lively and eccentric personality, and his strong and charismatic leadership qualities, as well as his confidence, fair-play, and professionalism, which made him an excellent organiser of the defence and a popular figure among the fans; as such, due to his cheerful attitude on the pitch and humorous demeanor, he earned him the nickname El Simpático ("Mr. Nice Guy," in Spanish) during the 1986 World Cup in Mexico. He also excelled at quickly rushing off his line; moreover, although he was not the tallest goalkeeper, his large hands aided him when coming out to claim the ball, which made him an authoritative presence in goal. Furthermore, he was renowned for his penalty–stopping abilities. Despite his goalkeeping ability, however, and his reputation as one of the best goalkeepers in the world in his prime, and as one of Belgium's greatest goalkeepers ever[6] – with some in the sport even ranking him as one of the best goalkeepers of all time –, he was also known to be inconsistent and prone to occasional errors.[a]
Pfaff was named by Pelé as one of the top 125 greatest living footballers in March 2004. He was a representative of company United Sol Energy in 2005. The company became the sponsor of the former East German record championBFC Dynamo before the 2005-06 season. Pfaff became a member of BFC Dynamo and promoted the establishment of a new youth sports school at the club.[22] The new youth sports school at BFC Dynamo was meant to bear his name.[23] Pfaff visited the Sportforum Hohenschönhausen and participated in training with youth teams of BFC Dynamo.[24] However, the sponsorship never materialized. Pfaff resigned from the club on 11 August 2006 and terminated his membership.[25] He was a TV star in Belgium and the Netherlands with the reality show De Pfaffs showing him and his family from 2002 to 2012.[26]