Olaru was a successful junior player. She was the runner–up in both singles and doubles at the 2005 French Open, and captured the 2006 US Open doubles title along with Mihaela Buzărnescu. Her best professional grand slam result so far has been the third round of the 2007 French Open, when she defeated the 30th seed Julia Vakulenko in straight sets and lost to eventual runner–up, the 7th seed Ana Ivanovic. Olaru reached her highest singles ranking, World No. 53, on 27 July 2009, and her highest doubles ranking, No. 82, on 22 March 2010.
Ioana Raluca Olaru currently resides in her hometown Bucharest. Her parents, Adrian and Doina, run a convenience store together. Her sister Cristina is sixteen years older than Olaru, and lives in London. Olaru began playing tennis aged seven, and cites Kim Clijsters,Martina Navrátilová and Roger Federer as her role models. She graduated from school in 2007, and is fluent in Romanian, English, French and Spanish.
Olaru considers being a fighter as her biggest asset. She cites clay as her favourite surface and backhand down the line as favourite shot, but she can play well on all surfaces and she likes mixing up her game with drop shots. Olaru is currently coached by former player Michael Schapers.