[2] He also opened a Sunday school in Bush River Neck, Maryland, for African-American slaves, teaching them to read the Bible.

Shortly thereafter, on May 26, 1826, he married Lydia Morris and established a home in Kennett Square, Pennsylvania, that came to be known as "The Pines" and was used as a safe house for the Underground Railroad.

[1] He purchased The Pines from Jonathan and Ann Thomas who were already active in the Underground Railroad, having used the home as a refuge for runaway slaves from 1805 to 1830.

[4] His home was approximately 1 mile east of the historical village of Kennett Square, which was a center point of the abolitionist movement in southeast Pennsylvania.

[7] In the late 1830s, Fussell moved approximately 20 miles north of Kennett Square to West Vincent, Pennsylvania, to a farm neighboring his sister Ester Lewis.

At that location, he collaborated with Lewis, her daughters, in addition to Garrett and abolitionists John Vickers and Elijah Pennypacker in furthering the work of the Underground Railroad.

In 1851, he aided the escape of three participants in the Christiana Riot, providing the escapees with refuge in the Lewis family home in Chester County.

Fussell remained an active member of the Pennsylvania Anti-Slavery Society up until the end of the United States Civil War.

In 1846, Fussell organized a meeting of five local physicians and his niece Graceanna Lewis to discuss the desirability of women's careers in medicine.

[3] This meeting eventually led to the founding of the Female Medical College of Pennsylvania (later changed to Women's in 1867) in 1850, although he did not play a direct role in its creation.