As a young man, Jakob worked in Akkerwoude in the bakery of his uncle, Gerrit de Vries, who was married to his aunt Blijkje Antonides. Later Jakob worked in a bakery in Leeuwarden. Jakob's uncle Sake Antonides had a bakery in Veenwouden which he ran with his sisters Grietje and Eltje Antonides. When his uncle Sake became ill, Jakob returned to Veenwouden to live at the bakery and to help his aunts run it. When Sake died, Jakob took over the bakery.
When Jakob was 31 he married Jantje Bottinga, and they had four children. Jantje died in 1901, a few days after giving birth to a daughter, Lysbeth. In 1911 Jakob married Dirkje de Jong, and together they had six children.
Jakob was asthmatic. In about 1926 as his health declined, he sold the bakery to his son Pieter and moved into a house with an attached grocery store across the street.
