She started playing table tennis while recovering from scarlet fever when she was eight. In 1933, at age 12, she won the Romanian Cup. She won the Romanian national women's championship in 1936. She remained Romania's female champion for the next 21 years (1936–57, excluding World War II). Her first major win was the 1938 Hungarian Open.
Her career was interrupted by World War II, as from 1940 to 1944 she was barred from even entering a gymnasium in Romania and was unable to play.
Rozeanu won her first World Championship in 1950, starting the winning run that would see her win the championship six years in succession, a feat yet to be matched. She was also the last non-Asian woman to win the title. In total, she won 17 world titles (and 12 silver and bronze medals at the World Championships), three world women's doubles titles,and three world mixed doubles titles. By far Romania's greatest profile in the sport, she was also the President of the Romanian Table Tennis Commission from 1950 to 1960.
Rozeanu emigrated to Israel in 1960. She won the Maccabiah Games Table Tennis Championship in 1961 and she was Israel's champion three times, between 1960–62. She kept in touch with her native Romania, and visited it for the last time in 2005. In 2006 she died at the age of 84.
Rozeanu was given the Romanian title of Merited Master of Sport in 1954. She has also received four Order of Work honors. In 1997 she was awarded the Knesset Medal. She was awarded the title of Honorary Citizen of Haifa in 2001.