During his tenure as mayor, he focused on beautifying the city, specifically with the planting of a large number of oak and blue gum trees.

In recognition of this, the city council, in 1895, named the area next to the Molteno Reservoir, which was laid out and planted, De Waal Park.

[3] During the 1880s, De Waal travelled extensively, visiting Western Europe, the Middle East and North America.

His travels provided De Waal with material for his writing and he wrote several articles that appeared in Dutch-language publications at the Cape.

Two of the sons became prominent member of the community, the elder, Jan Hendrik Hofmeyr de Waal, became speaker of the Union parliament, and the other, Pieter de Waal, a clergyman of the Dutch Reformed Church.