She is generally considered to be one of the greatest woman tennis players of all time. Graf won 22 Grand Slam singles titles. In 1988, she became the only player to achieve the "Golden Slam" � capturing all four Grand Slam singles titles and the Olympic gold medal in the same year. She was ranked the Women's Tennis Association's No. 1 player for a record 377 weeks (the longest of any player, male or female, since rankings began) and is the only player, male or female, to have won all four Grand Slam singles tournaments (Wimbledon, the US Open, the French Open and the Australian Open) at least four times each.

A notable feature of Graf's game was her versatility across all playing surfaces, exemplified by her winning 6 French Open singles titles (second to Chris Evert) and 7 Wimbledon singles titles (third behind Martina Navratilova and Helen Wills).

Graf is married to the former World No. 1 men's tennis player Andre Agassi.

Steffi was introduced to tennis by her father Peter Graf, a car and insurance salesman and aspiring tennis coach, who taught his three-year-old daughter how to swing a wooden racket in the family's living room. She began practising on a court at the age of four and played in her first tournament at five. She soon began winning junior tournaments with regularity, and in 1982 she won the European Championships 12s and 18s.

Graf played in her first professional tournament in October 1982 at Filderstadt, Germany. She lost 6-4, 6-0 to Tracy Austin, a two-time US Open champion and former World No. 1 player. After the match, Austin seemingly dismissed Graf's abilities, saying there were "hundreds" of kids like her in the United States. (In their only other career match, Graf defeated Austin 6-0, 6-0 at Indian Wells in 1994.)

At the start of her first full professional season in 1983, the 13-year-old Graf was ranked No. 124. She won no titles in the next three years, but her game improved consistently and her ranking steadily climbed: to No. 98 in 1983, No. 22 in 1984, and No. 6 in 1985. In 1984, she represented West Germany in the tennis demonstration event at the Olympic Games in Los Angeles and won the gold medal. Her schedule was closely controlled by her father, who limited her play so that she would not burn out as many young tennis stars had. In 1985, for instance, she played only 10 events leading up to the US Open, whereas another up-and-coming star, Gabriela Sabatini of Argentina, who was a year younger than Graf, played 21. Peter Graf also kept a tight rein on Steffi's personal life. Social invitations on the tour were often declined as Steffi's focus was kept very much on practising and match play. Working with her father and then-coach Pavel Slozil, Graf typically practised for up to four hours a day, often heading straight from airports to practice courts. This narrow focus meant that Graf, already shy and retiring by nature, made few friends on the tour in her early years, but it led to a steady improvement in her play.

Graf finally won her first tour title in April 1986 at Hilton Head, South Carolina, defeating Chris Evert in the final. She followed this up with seven further tournament victories in 1986 and finished the year ranked No. 3.

The main weapon in Graf's game was her powerful forehand, which earned her the nickname "Fraulein Forehand." Over time, Graf also developed the best slice backhand in the game, as well as a consistent volley. She built her powerful and accurate serve up to 105 mph. She was also extremely fast and athletic, chasing down balls that seemed unplayable. Though she chose tennis as her career, she was also a top 400-metre runner in her youth and could potentially have been a world-class athlete in that event.