Karl Junker was born in the city of Lemgo on August 30, 1850, as the son of a blacksmith. He grew up with his grandfather because his parents had died young. Junker was two years old when his mother passed away and seven when his dad died. He went to school in Lemgo, graduated in 1866 and started his vocational training as a carpenter.

In 1869, he worked in Hamburg as a journeyman carpenter.

He moved to Munich in 1871, where he studied art – at first at the Kunstgewerbeschule (School of Arts and Crafts) and then from 1875 on at the Akademie der Bildenden Künste (Academy of Fine Arts).

In the fall of 1877, he went on a study trip to Italy for two years and returned to Lemgo around 1881. Eight years later, Junker started the planning and design of his house on a piece of land on the outskirts of the city.

From 1891 he lived and worked as an artist in his house.

On January 25, 1912 he died of pneumonia.

In April/May of 1914 – two years after his death – several pieces of his works were displayed in the sixth exhibition of the New Berlin Secession.