Dorothy played outfield for a local softball league, and at the age of 17 she was spotted by a scout from the All-American Girls Professional Baseball League. After tryouts in Chicago, she joined the Rockford Peaches as an outfielder when the league began in 1943, but was soon playing first base. She and second baseman Snooky Harrell formed the league’s best double-play combination.
Dorothy played with the league for 10 seasons, and was selected as an All-Star all seven times the league established such a team. In 1946 she was the league's top batter with an average of .316, and won the distinction again in 1947 with an average of .306. She struck out only 81 out of 3,736 times at bat.
Considered one of the best athletes of her time, southpaw Kamenshek was even recruited for men's baseball by a team from Fort Lauderdale, Florida. She believed the team only wanted her for publicity and turned down the offer.
In the off‑seasons, Kamenshek studied physical education and health education at the University of Cincinnati. In 1951 she was forced to reduce her playing due to back injuries, and after the 1952 season she retired permanently from the game with a career average of .292.
In 1958, Kamenshek received a degree in physical therapy from Marquette University in Milwaukee. She returned to Ohio to serve as a physical therapist in Hamilton County and later moved to Los Angeles to perform the same work at the Los Angeles Crippled Children's Services Department. In 1964, she was promoted to supervisor of physical and occupational therapy for Los Angeles County Children's Services, and later to chief of therapy services, the position she held when she retired in 1980.
After her retirement, Kamenshek was honored by Los Angeles County with the Outstanding Management Award (1980).