Frederick Leinbach was born around 1817 in Pennsylvania to Elias and Mary Leinbach. His father was a clockmaker and was probably part of the Mennonite community. They lived in Lancaster County, Pennsylvania, and he worked as a schoolteacher in the late 1840s. A local writer later claimed that his “principal fitness for the business of teaching consisted in his utter unfitness for anything else. He was a quiet, unoffending being, whose mental and physical weakness effectually put him under bonds to keep the peace with everybody. Being poor, and incapable of earning his bread by manual labor, his friends thought it would be no disgrace for him to ‘keep school.’”
By 1850, Leinbach was working as a shoemaker. A decade later, he was a bench maker, and he owned $1,100 of real estate and $200 of personal property. He helped care for his elderly parents, who both died in the early 1860s. He eventually married Fannie Brubaker, and they settled in Union, Pennsylvania. By 1880, he was working as a farm laborer. He died in 1886.