Philemon Beecher Ewing was born on November 3, 1820, in Lancaster, Ohio, to Thomas and Maria Ewing. His father was a Whig politician who served two terms as a United States Senator and served as a cabinet member under William Henry Harrison and Zachary Taylor. His brother was
Charles Ewing, a University of Virginia alumnus who served in the Union army during the Civil War.
He married Mary P. Gillespie on August 31, 1848, and they had at least eleven children: Thomas, born around 1850; Mary, born around 1852; Eleanor, born around 1853; John, born around 1858; Francis, born around 1859; Rebecca, born around 1861; Angela, born around 1863; Neal, born around 1865; Philomena, born around 1867; Theodosia, born around 1869; and Edward, born around 1870. He worked as a lawyer in Lancaster, and by 1850, he owned $2,200 of real estate. A decade later, his wealth had grown to $57,500 of real estate and $16,500 of personal property.
He supported the Union Party during the Civil War, and in March 1862, he received an appointment as a judge on the court of common pleas. He remained in Lancaster for the rest of his life, and he died there of acute paresis on April 15, 1896.