She was born to the concert singer Mathilda Berwald and the musician Johan Fredrik Berwald. She and her sisters Fredrique and Hedvig Eleonora were trained as singers by their mother, and sang with her at their fathers concerts. They performed in Finland (1842), Copenhagen (1844) and Berlin (1847). The three siblings were also a popular singing trio.
In 1847, she was employed at the Royal Swedish Opera in Stockholm. In 1848, she was contracted as premier actress. During her years at the Opera, she became one of the greatest stars of the Swedish opera. Julie Berwald was elected to the Royal Swedish Academy of Music, as member no. 337 on 16 December 1853.
In 1852, she married Baron Georg Gustaf Knut Åkerhielm. Her marriage met with no resistance from the nobility, indicating a change in attitude towards singers and actresses, who were long looked down upon socially.