Joseph "Matthias" Leinenkugel was born in Adendorf, Rheinland, Prussia. He emigrated with his family to America at the age of nine.

His father Mathias Jacob opened a brewery in around 1850 in Sauk County, Wisconsin. It was here that young Mathias and his four brothers learned the art of beer making. Five years later at the age of twenty, Matthias journeyed 150 miles northwest to the town of Eau Claire, Wisconsin to form his own brewery. He was perhaps drawn to the town by its name, which translated means "Clear Water".

In 1855 Eau Claire was a lumber town nicknamed the "Sawdust City". The majority of its 100 or so residents worked in sawmills. The dangerous and laborious work made for a lot of stressed-out young men nursing aches and pains, the perfect clientele for Joseph's new brewery on Madison Street. He named the brewery the Eagle and it was a success from the start.

But success wouldn't last long enough. In 1874 he contracted a disease of the Kidneys, which was complicated by Typhoid Fever. Matthias died on October 15th, at age 38 years. His mother Theresia took over Eagle Brewery after Matthias's death until 1885, at which time his son Joseph Matthias turned twenty and became manager. The young son was apparently not inclined to operate a brewery so in 1888 he sold the brewery to Henry Michels, who ran the firm until 1912. But soon after selling, the junior Joseph Mathias Leinenkugel contracted an ailment of the kidneys, just as his father did, and died in 1892 at the young age of 32 years.