According to the Philadelphia Architects and Buildings Project [http://www.philadelphiabuildings.org/pab/app/ar_display.cfm/22852], the architect was Stephen Decatur Button. From their site:

Born: 6/15/1813, Died: 1/17/1897

"Stephen D. Button has been characterized by his biographer as "a capable, financially successful architect much in demand in the Philadelphia area" in the mid-ninteenth century. Born in Preston, CT, and apprenticed for five years to a carpenter at the age of sixteen, Button moved to New York City after gaining his freedom where he became an assistant to the architect George Purvis, with whom he remained for about two years. Striking out on his own, Button worked independently for a decade in the Hoboken, NJ, area. In the mid-1840s he moved south, working in Florida and Georgia in 1845-46.

In the latter year he entered and won the competition for the Alabama State Capitol in Montgomery with a Roman Revival design. Relocating to the Philadelphia area, he formed a partnership with his brother-in-law, Joseph C. Hoxie, in 1848. This formal relationship continued until c.1852 when it was dissolved by mutual agreement. The earliest known Hoxie & Button design is the Egyptianesque Odd Fellows' Cemetery Entrance, built c.l849 in Philadelphia. By the 1850s, however, Button appears to have fully embraced the picturesque, eclectic, and flexible Italianate style that would characterize most of his important commissions, such as the Spring Garden Institute (c.1851-52), and the Romanesque First Baptist Church (1853-56). In 1854 Button entered the competition for the Academy of Music and secured the second premium after the winning design of Lebrun and Runge.

A successful contemporary of Thomas Ustick Walter and Samuel Sloan, Button was one of the organizers of the Pennsylvania Institute of Architects in 1861 which later became the Philadelphia Chapter of the American Institute of Architects. His practice was largely confined to Philadelphia, Camden, NJ, where he designed the City Hall and several schools and churches, and New Jersey shore communities. He was succeeded in his office at 430 Walnut Street by Schermerhorn & Reinhold."

Written by Roger W. Moss.