Along with his father, on 11 December 1799, he was among the last guests at Mount Vernon before George Washington died.

Fairfax birthed children with Mary Aylett, a Native Indian woman.

He had seven children by his third wife Margaret:[4] He maintained a winter home at 607 Cameron Street, Alexandria, Virginia, which he built in 1816.

Because of these religious beliefs, he manumitted his slaves (including the great-great-great grandfather of Virginia Lieutenant Governor Justin Fairfax[6]), some of whom he taught a trade and sent to Liberia.

[2] Thomas Fairfax was referenced by astrophysicist Neil deGrasse Tyson on rap musician Logic's 2017 album Everybody on the song "Waiting Room.