He spent much of his early career mixing, recording, releasing, and archiving a broad cross-spectrum of South African music.
Marks achieved success with his songwriting, penning some international hits, most notably "Master Jack", "Mr. Nico", and "Hey Mister"—songs that Marks wrote prior to 1967 whilst working underground in South Africa’s Free State gold mines.
Marks amassed a collection of material that documents South African music from the mid 1960s to the early 2000s.
In 1990 Marks formed the Hidden Years Music Archive Project to safeguard and preserve the material he collected.
[2] This collection was donated to the Documentation Centre for Music at Stellenbosch Universityin 2013 where it is managed by Dr Lizabé Lambrechts in collaboration with Marks.