Van Niekerk was born in Edenburg and matriculated at the Edenburg High School. In 1949 he was awarded a Bachelor of Arts degree by the University College of the Orange Free State in Bloemfontein, and later an honours degree in Philosophy at the University of South Africa (Unisa). He finished his studies in 1950 and graduated with an honours degree in Philosophy at Unisa in 1950.
In 1967, he was awarded a Master of Arts degree by the University of Pretoria.
In 1978, he became an Emeritus Professor of the University of Pretoria, a position he held until his retirement in 1994.
In 1950 he became a radio presenter and producer. In 1957, he became the head of the radio department for the Department of Agriculture, and later the Head of Radio for the whole broadcasting network. van Niekerk"s first work, a book of poems, Standpunte, was published in 1953. He also was writing prose and radio plays and writing for television
His novel Gannavlei, was published in 1958.
He was awarded the Eugène-Marais Prize in 1963, for his collection of short stories.
He is one of the most influential Afrikaans-language writers as a member of Sestigers.