Clem Koester was born on September 18, 1835 in Prussia, Germany. His parents were Barney Koester (40) and Elizabeth (maiden name unknown) (41).

In 1860, he was living with his parents on their farm, in Effingham County, Illinois. He was listed as Clemess B. and his occupation was farming.

Between 1860 and 1865 he married Elizabeth Kramer.

By 1870, he was living in Douglas Township, Effingham County, Illinois. He was going by the name Barney C. and he was a farmer. He had real estate worth $500 and personal estate worth $300. Living with him at that time was his wife Elizabeth of 25 years, and his three sons Henry of 5 years, Barney of 3 years, and Agornises of 6 months.

Clem Koester died on September 8, 1916.