He was editor-in-chief of the Afrikaans weekly family magazine Huisgenoot, as well as its English sister publication, You.

By the late 1970s, weekly sales of Huisgenoot dropped to 129,000,[citation needed] leading the publication's owners to consider shutting it down.

It was read by more than two million people every week, based on an average issue readership of more than four per copy sold.

As with Huisgenoot, Hammann had You's content meet international standards, which he had previously studied as London editor for Naspers's magazines.

Naspers awarded him their highest accolade, while the South African Academy for Science and Arts (Afrikaans: Die Suid-Afrikaanse Akademie vir Wetenskap en Kuns) awarded him their medal for excellence in journalism.