Despite having almost no knowledge of the English language when he arrived, he performed well academically and also developed into an outstanding squash player who, by 1962, had won every public school title open to him including the public schools under-15 championship (three times), the public schools under-16 championship, the Evans Cup, and the Drysdale Cup (considered at the time to be the unofficial world junior championship).

In 1970, he reached the semi-finals of the British Open (which was considered to be the effective world championship of the sport at the time).

Khan's greatest achievements came on the North American hardball squash circuit.

Three other brothers, Gulmast, Liaqat Ali ("Charlie"), and Salim ("Sam"), also competed in top-level hardball squash.

In 2004, Khan became the first non-US citizen to be inducted into the United States Squash Racquets Association Hall of Fame.