Susan Apthorp Bulfinch, daughter of Grizzell Eastwick and Charles Apthorp, was a lifelong member of King's Chapel. She had a privileged upbringing, with "every advantage that leisure, affluence, and affection could afford to improve the strong and ardent mind." Like her mother's wealth, however, this upbringing came at a cost: her father was a major importer of enslaved people in colonial Boston and her family enslaved several people in their home. Susan married prominent physician Dr. Thomas Bulfinch, II, and the couple had several children, including architect Charles Bulfinch. At King's Chapel, Susan had the responsibility of handling the collection plate money, including investment and distribution to the church's charitable interests. While little is known about Susan's early life, she became a prolific letter writer in her later years. Her letters shed light on how she viewed the world around her, as she shared her thoughts and reflections on life in Boston at the turn of the 19th century with her brothers in England. Above all, though, Susan loved to read and loved being a grandmother. She wrote extensively about her own grandchildren, and wrote about herself that "I am the universal Grand Mama of all my young acquaintances & delight to contribute to their pleasures, convinced that the life abounds with sources of enjoyment the season for improving them is transient and should not be ungratefully neglected." When Susan passed away in 1815 at age 81, she was buried in her husband's tomb beneath this church.