The core band members were Tina Cross (a native of New Zealand) and Leon Berger (Australian), who met in Sydney.
In 1984 Cross, who was a successful singer in New Zealand (having four top 50 singles and won the 1979 Pacific Song Contest), moved to Australia and formed the band with Berger, who was born in Russia and studied at the Moscow Conservatory of Music. Berger and Cross having previously met at a song contest in New Zealand. Koo De Tah scored a hit in 1985 with their debut single, "Too Young for Promises", which reached Number six in the Australian singles charts and Number 48 in New Zealand music charts. The song was released in and received major airplay in many territories around the world.
The band's self-titled debut album was released in 1986. "Too Young For Promises" was featured in the 1984 film "Streets Of Fire", starring Michael Paré and Diane Lane.
The band was active from 1984 to 1987.