In his youth, Poul Mark worked as a servant close to his hometown. In 1912, he was a member of the Danish gymnastics team that won silver behind Sweden in the Swedish system at the Stockholm Olympics. He was trained as a carpenter and lived in Ry, now part of Skanderborg municipality. From 1913-17 Mark worked in the United States as a drainage master. After returning to Denmark, he worked as a carpenter again in Skjern in Central Denmark. From 1920, he was a farmer in the region of Skjern and – after 1929 – in Skarrild, also in Central Denmark.
In 1918, Mark married Kirsten Vestergaard Madsen. Within a period of 17 years, they had 12 children, seven daughters and five sons, but four of them died in their infancy.