Asa Matlack Stackhouse was born in Philadelphia on July 21, 1845, the son of Robert Stackhouse and Ann Roberts Matlack. He received his early education in public and private schools in Moorestown, New Jersey.
In 1863 Stackhouse entered the class as a junior in the Class of 1865. During his college years he was a a member of the Zelosophic Society. In 1868 he was awarded both an A.M. from the University as well as an M.D. from the Homeopathathic Medical College (later Hahnemann Medical College), Philadelphia.
The following December, Stackhouse married Ella Jane Romig, the daughter of William Jacob Romig, a doctor at Jefferson Medical College. They were married in Allentown, Pennsylvania where Stackhouse practiced medicine until 1871; he then engaged in the insurance business until his retirement in 1891.
A member of a number of historical and genealogical societies, Stackhouse served for many years as the curator of the Burlington County (New Jersey) Historical Society. He was also the author of a number of published genealogies and histories, including Maladies, Remedies and Physicians of Colonial Days in Burlington County New Jersey and a biography of one of his ancestors, Timothy Matlack. Stackhouse died on October 16, 1916, in Moorestown, New Jersey. A grandson of the same name was a 1923 graduate of the University of Pennsylvania Law School.