A 1956 graduate of Muskegon High School, DeHoog picked up tennis at a young age when there were limited high school sports opportunities for females.  As a member of the Muskegon Tennis Club, Rosemary had earned a reputation as one of the top players in the state by her senior year in high school. Competing in top events around Michigan, like the Michigan State girls open tennis tournament at Kingswood School of Cranbrook, Luther earned the opportunity to play at Kalamazoo College.

There, she won the MIAA women’s singles championship in all four years at Kalamazoo College from 1957-60 and was a semifinalist in the USLTA College Girls Tennis Championships at St. Louis in 1959, losing to second-ranked Carol Loop  of San Bernardino College. Loop would later play at Wimbledon. DeHoog remained a nationally-ranked player in her age group for many years. After moving to New York state, she became certified as a teaching professional and official. In 1986, she was among the first class of 14 inducted into Kalamazoo College’s Athletic Hall of Fame.

From 1979-2003, DeHoog was the head tennis professional at Drumlins Tennis Club, which is owned by Syracuse University, and was an adjunct professor at Syracuse from 1978 through 2004, teaching recreational tennis to students. Over the years, she served on numerous boards for tennis organizations and has been honored by the Big East Conference for advancing girls and women’s sports. In 2012, she was inducted into the United States Professional Tennis Association’s Eastern Division Hall of Fame, encompassing New York and part of New Jersey. In February of 2018, Syracuse renamed Court One at Drumlins in her honor.