Boonzaier had no formal art tuition, but closely studied the work of George du Maurier and Phil May of Punch fame.In 1889 he resigned from his job in the civil service and became a professional cartoonist.

[2] In 1891 he started work on a gallery of South African and foreign notables and persuaded them to sign their caricatures; included are Paul Kruger, Piet Joubert, Ellen Terry, Sarah Bernhardt, Henrik Ibsen, Leo Tolstoy, Émile Zola, Alphonse Daudet and Pierre Loti.

[3] The collection is of great historical interest, as it depicts virtually all the main political actors of the time: Lord Milner, Cecil Rhodes, Gordon Sprigg, John X. Merriman, J. W. Sauer and W. P. Schreiner; Sirs John Henry de Villiers, Henry Juta and James Rose Innes; and Boer leaders like Paul Kruger, Marthinus Steyn, Louis Botha, Christiaan de Wet and F. W. Reitz.

[5][6] Boonzaier's cartoons were powerful propaganda for the NP's resurgent Afrikaner nationalism, which opposed Louis Botha and Jan Smuts' relatively pro-Imperial and free-market South African Party.

[6] Though Botha had been a prominent bittereinder during the Boer War, as South Africa's first Prime Minister he was perceived as naively conciliatory and pro-Imperial, and became a regular target of Boonzaier's caricatures.

Certainly Boonzaier's cartoons expressed contempt for mining interests on the Rand, whose supposed exploitation of poor Afrikaners Smuts' government did little to prevent.

[6] These sentiments intensified when Smuts brutally suppressed the 1922 Rand Revolt, after which Hertzog swept to election victory over him and initiated a series of measures to protect white workers.