Elizabeth was born into the upper class of New York society, and raised Episcopalian. In spite of her high society background, Elizabeth’s early life was quiet, simple and at times, lonely. Her father, Dr. Richard Bayley, was the Chief Health Officer of the Port of New York, attending to immigrants arriving at Staten Island.
Her mother, Catherine Charlton, was the daughter of a Church of England minister who served as the rector of St. Andrew’s Church. Catherine died when Elizabeth was only three years old.
After her mother’s death, Elizabeth’s father saw that she received an excellent education. To provide a mother to his two young daughters, Dr. Bayley married Charlotte Amelia Barclay. The new Mrs. Bayley was a member of the Jacobus James Roosevelt family and actively participated in social ministry. Elizabeth accompanied her stepmother on her charitable rounds from visiting the poor to distributing food.
Elizabeth fell in love and in 1794 married the wealthy William Seton. Their first years together were happy and prosperous. Elizabeth and William were blessed with five children: Anna Maria (Annina) (1795–1812), William II (1796-1868), Richard (1798–1823), Catherine (1800–1891) (the first American to join the Sisters of Mercy), and Rebecca Mary (1802–1816).
In marriage, Elizabeth actively engaged in social ministry by nursing the sick and dying among family, friends, and needy neighbors.
She became a charter member of The Society for the Relief of Poor Widows with Small Children in 1797 and became the organization’s treasurer.
Within four years of their marriage, William’s father died. His passing left the young couple in charge of William’s seven half brothers and sisters, as well as the family’s importing business. The business began to fail due to a myriad of reasons — most devastating blows were caused by politics of the time and sanctions. Simultaneously William’s health began to fail. He was forced to file a petition of bankruptcy before setting sail for Italy, in a final attempt to save his health.