Sonnenberg was the only son of Louis Sonnenberg and his wife, Mathilde Strauss. Two of his uncles, Charles and Isaac (Ikey) emigrated to
Griqualand West to join the early
diamond mining industry there, and Max's father, a teacher, and his family persuaded him to follow their example in 1891. Charles was elected to the
Parliament of the Cape of Good Hope in 1896. Louis's family first lived in the village of
Madibogo, where he managed a two-room hotel in partnership with S. Solomon & Co. They later moved to
Vryburg, where Louis owned a store. After a time working as a traveling salesman along the railways being built through
Bechuanaland and
Rhodesia, Sonnenberg opened a grocery in
Bulawayo in 1898. After the
Second Boer War, he returned to Vryburg, where he farmed and continued to grow his
mercantile career; he served as
mayor of the town (1919–20) after being elected to the city council in 1912. He was a founder of Bechuanaland Dairies, which was later acquired by Royal Dairy Ltd. He persuaded the city to spend £40,000 to build a reservoir to mitigate chronic water shortages. During the 1918
Spanish flu pandemic, he contributed money to the Vryburg Hospital to buy equipment, for which he was later compensated unexpectedly, and built a
soup kitchen in which he and his wife both worked. == In Cape Town ==