Diana Ionescu was born in Constanţa (Romania). At the age of 5 she received her first ballet lessons, later she attended the Colegiul National de Arte Regine Maria Constanţa in her home town. In 2014 she continued her education at the Tanzakademie Zurich where she graduated in 2017.

In 2013 she won the first prize in the junior category at the Youth America Grand Prix. In 2016 won the gold medal at the Tanzolymp in Berlin. At the Prix de Lausanne 2017 she won a scholarship. In the 2020 Critics' Choice of the dance magazine tanz she was named as "Dancer of the year".

At the beginning of the season 2017/18 Diana Ionescu became an apprentice with the Stuttgart Ballet. Already at the beginning of November 2017 she was taken in the Corps de ballet. In the 2019/20 season she was promoted to Demi-Soloist. Already one season later she was promoted to Soloist.