Rankin was born St Louis, Missouri. At 14-years-old, she won the Missouri Amateur. At 15, she was the low amateur in the U.S. Women's Open. She then turned pro at 17 years of age.

Rankin won twenty-six events on the LPGA Tour. She topped the money list in 1976 and 1977 and finished in the top ten on the money list eleven times between 1965 and 1979. However, she did not win a major championship; her best finishes were a clear second at the 1976 LPGA Championship and tied seconds at the 1972 Titleholders Championship, 1972 U.S. Women's Open, and 1977 LPGA Championship. Rankin did win the Colgate Dinah Shore Winner's Circle (currently the Kraft Nabisco) in 1976 and the Peter Jackson Classic (later renamed the duMaurier) in 1977, two events that would later be elevated to major status, but they are not counted as majors in the years in which Rankin won.

Rankin was LPGA Player of the Year twice and won the Vare Trophy for the lowest scoring average three times. She retired from full-time competition at the age of 38, due to chronic back problems. She captained the victorious American teams in the 1996 and 1998 Solheim Cups. Rankin became the first player voted into the LPGA Tour Hall of Fame in 2000 under the veterans category, and she was also inducted into the World Golf Hall of Fame in 2000.

In 2002, she was voted the Bob Jones Award, the highest honor given by the United States Golf Association in recognition of distinguished sportsmanship in golf. Rankin is a golf commentator for the TV networks - ABC and ESPN. She has also been a professional advisor for the magazines Golf Digest and Golf For Women.

Rankin played as Judy Torluemke until she married Walter Rankin, known as "Yippy", in 1967. They lived in Midland, Texas. They have a son, Walter Jr., known as "Tuey," born in 1968.

Tuey's wife is PGA Tour golfer Geoff Ogilvy's sister-in-law.

Rankin was diagnosed with breast cancer in May 2006. She completed treatment by August, 2006 and returned to her on-air work on ABC in time to cover the Women's British Open.

LPGA wins (26)

• 1968 (1) Corpus Christi Civitan Open
• 1970 (3) George Washington Golf Classic, Springfield Jaycee Open, Lincoln-Mercury Open
• 1971 (1) Quality First Classic
• 1972 (2) Lady Eve Open, Heritage Village Open
• 1973 (4) American Defender-Raleigh Classic, Lady Carling Open, Pabst Ladies Classic, GAC Classic
• 1974 (1) Baltimore Classic
• 1975 (1) National Jewish Hospital Open
• 1976 (6) Burdine's Invitational, Colgate-Dinah Shore Winner's Circle, Karsten-Ping Open, Babe Zaharias Invitational, Borden Classic, Colgate-Hong Kong Open
• 1977 (5) Orange Blossom Classic, Bent Tree Classic, Mayflower Classic, Peter Jackson Classic, Colgate European Women's Open
• 1978 (1) WUI Classic
• 1979 (1) WUI Classic

Note: Rankin won the Colgate-Dinah Shore Winner's Circle (now known as the Kraft Nabisco Championship) and the Peter Jackson Classic (which became the du Maurier Classic) before they became major championships.

Other wins (2)

• 1974 (1) Colgate European Open
• 1977 (1) LPGA National Team Championship (with JoAnne Carner)