Jack Kramer began his tennis career by taking lessons from teaching professional, Dick Skeen. Within a year, he was playing junior tournaments. He played on the Montebello High School tennis team with George Richards. Because of his obvious ability and his family’s lack of money, he came under the guidance of Perry T. Jones. at the Los Angeles Tennis Club (LATC). Jones was the President of the Southern California Tennis Association (SCTA). Kramer traveled many hours each day from his home in Montebello, California, to play tennis at the LATC and the Beverly Hills Tennis Club. He was able to play against such great players as Ellsworth Vines, Bobby Riggs, and Bill Tilden. He was the National Boys’ Champion in 1936, and the winner of the 1938 National Juniors Interscholastics. He competed occasionally in men’s tournaments on grass courts in the East. He won matches against nationally ranked men such as Elwood Cooke. He also played with high school teammate, George Richards, who later was nationally ranked. Jack Kramer competed at the U.S. National Championships seven times from 1938 through 1947. He lost his first match in 1938 in straight sets, winning only two games. At the 1939 U.S. Championships he was beaten in the second round by 11th-seeded and fellow Californian Joe Hunt. In 1940 Kramer defeated fourth-seeded Frank Parker in a five-sets quarterfinal but lost to second-seeded and eventual champion Don McNeill in the semifinal. At the 1941 Championships he was seeded for the first time, at No. 11, and reached the quarterfinal where third-seeded Francis Kovacs proved too strong. Kramer received a leave from his duties in the Coast Guard to compete at the 1943 Championships. Seeded second, he reached the final, despite being weakened by food poisoning, but lost it to Joe Hunt in four sets. During World War II he continued to win prizes in the United States, since the war had effectively put an end to international tennis, but did not compete in the U.S. Championships in 1944 and 1945.

The first Grand Slam tournament Jack Kramer entered after the war was the 1946 Wimbledon Championships were he was seeded second but was upset in by Jaroslav Drobný in a five-set fourth round match. At the 1946 U.S. Championships he was seeded third but managed to win his first Major singles title after a straight-set victory in the final against Tom Brown, losing just a single set in the tournament. At the 1947 Wimbledon Championships Kramer was seeded first and justified it by winning the title after another straight-sets win against Brown in a final that lasted only 48 minutes. Jack Kramer made his debut for the US Davis Cup team in 1939 in the final of the World Group against Australia. Together with Joe Hunt they lost the doubles match against John Bromwich and Adrian Quist. In 1946 and 1947 he was part of the winning US team, defeating Australia in both finals and winning all four of his singles matches. After 1947 he became ineligible to play for the Davis Cup on account of becoming a professional player. He compiled a Davis Cup match record of seven wins and two losses. Kramer turned professional in November 1947, signing a $50,000 per year contract with promoter Jack Harris. He made his pro debut against Bobby Riggs on December 26, 1947 at Madison Square Garden. 15,114 people showed up for the match in one of the worst snow storms in New York history to watch Riggs win. Jack Kramer went on to win the tour with Riggs 69 to 20 and became the top professional for the next six years. Bobby Riggs and Kramer convinced Sarah Palfrey Cooke and Pauline Betz to turn professional and play matches prior to their main contest. 1947 Australian Championships winner, Dinny Pails, and four-time US Championships semifinalist, Pancho Segura, also turned professional in late 1947 and played against each other on the undercard of the 1948 Kramer vs. Riggs tour. He retired from competitive tennis in 1954 due to arthritic back problems and went on to promote his Pro Tour. He made brief comebacks on tours with Hoad and Rosewall in the late 1950s. Jack Kramer died from a soft tissue cancer on September 12, 2009 at his home in the Bel Air neighborhood of Los Angeles, California.