He was ranked as high as # 4 in the U.S. (in 1962). Between 1961 and 1968, he ranked among the top 10 men in the U.S. five times.
In 1960, he teamed up with Larry Nagler to capture the NCAA doubles title for UCLA. In 1961, as team captain, Fox won the NCAA singles title. During his college career Fox lost only two dual matches. "One was to Rafael Osuna and the other was to Chuck McKinley," he said. He was a three-time All-American, (1959-61), and also earned All-UCLA and All-University of California Athlete of the Year honors, which are presented to the Best Scholar-Athlete. Fox helped lead the Bruins to NCAA team championships in 1960 and 1961.
He was one of Arthur Ashe's closest friends Ashe's freshman year, when Fox was a senior. As Ashe put it, "In those days, to be Jewish in the top ranks of tennis was to encounter a certain amount of prejudice." Fox graduated from UCLA with a B.A. in physics and a Ph.D. in psychology.
Upon graduation, Fox was the 4th-ranked singles player in the United States.
He also won the singles title at Cincinnati in 1961.
In 1962, he reached the singles final in Cincinnati, falling to Marty Riessen.
In 1965 he reached the quarterfinals at Wimbledon.
He won the Canadian Nationals in 1966.
Fox also won the Mercedes-Benz Cup, formerly known as the Pacific Southwest, in 1966 when he was a graduate student, beating Manuel Santana aka "Manolo" Santana, Fred Stolle, Tony Roche, and Roy Emerson in the finals. Fox rode his motorcycle each day from UCLA to the Los Angeles Tennis Club.
Also during his career, he won the US National Hardcourt title.
Fox was elected to the Intercollegiate Tennis Association Hall of Fame as a player and a coach in 1988.
He was inducted into the Southern California Tennis Association Hall of Fame in 2002.
Fox coached the Pepperdine University men’s tennis team, at the highest level-Division 1, for 17 years. His teams, which included Brad Gilbert, reached the NCAA finals twice, the semifinals three times, and the quarterfinals six times.
He was named to the Intercollegiate Tennis Coaches Hall of Fame and coached players such as Brad Gilbert, Robbie Weiss (NCAA singles winner), Kelly Jones (tennis) (NCAA doubles winner and world No. 1 doubles player), and Martin Laurendeau (Captain of the Canadian Davis Cup Team).
After working as a broadcaster, Fox became a writer and a lecturer. Fox has authored several books, including Think to Win: The Strategic Dimension of Tennis, If I'm The Better Player, Why Can't I Win?, and his most recent book The Winner's Mind: A Competitor's Guide to Sports and Business Success.
He is also a former editor of Tennis Magazine.
Allen has also made videos entitled Allen Fox's Ultimate Tennis Lessons and Allen Fox's Ultimate Tennis Drills.