Gerda began her professional acting career in 1962 as a stage actor. However, in the following years much of her employment would concern television, and in 1964 she joined the cast of long-time running crime series Homicide as a guest star for the first time. Until 1975, Gerda would star in Homicide five times, every occasion as a different character.

Another long-time runner, in which Gerda starred several times was Hunter. In 1967 she acted in four episodes as Marion Tolhurst. The following year she shot another episode of the series, this time as Janet MacGregor in 'Message from Hong Kong'.

When the Seventies came, Gerda got employed as a regular in Bellbird. However, she continued to make other guest starring work in other series, such as Matlock Police, Ryan, Quality of Mercy and Young Ramsey.

In 1981, Gerda joined the cast of Prisoner as a guest star. She only filmed two episodes as the corrupt Mrs Roberts, but a couple of years later, she would join the cast permanently as Governor Ann Reynolds.