Klenner was born in Johnstown, Pennsylvania on October 22, 1907 to Mary (née Bewak) and Frank Klenner, the youngest of their eight children. His parents had come to the United States from Austria as children. When Fred was born, Frank and Mary were living on a farm near Johnstown, although Frank kept working at Bethlehem Steel Corp. where he had worked since a young man. In 1908, Fred's 16-year-old sister Gertrude died from respiratory problems caused or aggravated by smoke spewing from blast furnaces at Johnstown's steel mills. It was said that Fred was a smart child—some said, the smartest of all the Klenner children, sensitive and earnest. In his free time he enjoyed playing in an Austrian band and could play several instruments including the cornet, violin, harpsicord, zither and piano. Klenner attended St. Vincent College for two years and St. Francis College now Saint Francis University, Loretto, Pennsylvania where he received his B.S. and M.S. degrees in biology in 1931.
