With eight different partners, she won a total of 13 women's doubles titles in Grand Slam tournaments. Her last doubles title, at the age of 33 at the 1969 US Open, came six years after she had retired from serious competition to become a tennis instructor. She also played the US Open singles tournament in 1969, losing in the second round to Françoise Dürr 6–3, 6–3.
According to Lance Tingay of the Daily Telegraph and the Daily Mail, Hard was ranked among the top ten in the world from 1957 through 1963, reaching a career high of number 2 in those rankings in 1957, 1960, and 1961. Hard was included in the year-end top ten rankings issued by the United States Lawn Tennis Association from 1954 through 1963. She was the top-ranked U.S. player from 1960 through 1963.
Hard once said, "I was the last of the amateurs. In our day, I won Forest Hills and got my airfare from New York to Los Angeles. Whoopee." But, she added, "I was happy. I loved it. I loved tennis."