Borg was born in Sodertalje, Sweden, on June 6, 1956. When he was 9 he got his first tennis racket—the prize his father, a clothing salesman, won in a table-tennis tournament. For five years Björn took a train to Stockholm every afternoon after school to practice tennis for three hours, then play ice hockey. From the start he played with a Ping-Pong style, using his wrists to give the ball an exaggerated spin. His two-fisted backhand probably evolved from his hockey stroke, as well as from the weight of the racket. He converted from a two-handed to a one-handed forehand to perfect his topspin, but his early coaches decided not to tamper further with his unorthodox style.

Borg won his first tournament when he was 11. In four years he captured all the world's junior titles. He dropped out of school when he was in the ninth grade, at 15, and qualified for the Swedish Davis Cup team, becoming the youngest player ever to win a cup match. This was his first encounter with team captain Lennart Bergelin, who later became Borg's full-time coach. In 1975 Borg's three match victories (including doubles) brought Sweden its first Davis Cup.

In his first decade in competitive tennis, the golden-haired Swede compiled a record of career firsts that was the most wide-ranging in tennis history. His remarkable string of singles titles on the grass of Wimbledon (1976, 1977, 1978, 1979, 1980) and the clay of the French Open (1974, 1975, 1978, 1979, 1980, 1981) was unprecedented.

The widely circulated story that Borg's pulse rate was only 35 beats per minute was no doubt an exaggeration. His preference for extremely tightly strung rackets (80-pound tension) was unusual. His consistency, concentration, and speed on court were awesome. After his marriage to Mariana Simionescu, a Romanian tennis pro, on July 24, 1980, Borg cut back on his tournament play.