Fearing for his future, Jennings tried to arrange a purchase price with Madison, but she sold him to an insurance agent for $200 () in 1846. Six months later, Senator
Daniel Webster intervened to buy him from the new owner for $120 () and gave Jennings his freedom, for which he paid the senator in work. He entered the large free black community of Washington, which outnumbered enslaved people by three to one at the time. In 1848, Jennings helped plan a mass escape of 77 enslaved people from Washington, D.C., on the schooner
Pearl. It was the largest escape attempt by enslaved people in US history. John, Franklin, William and daughter Mary later joined him in Washington and the area. After the war, Jennings worked at the newly established
Pension Bureau, part of the
Department of the Interior, to handle claims of veterans and soldiers' families. He made the acquaintance of John Brooks Russell, an antiquarian. Russell wrote it down because of Jennings's story of his years with Madison. He published it for him in January 1863 in
The Historical Magazine and Notes and Queries Concerning the Antiquities, History and Biography of America, to which Russell had contributed. He helped Jennings gain publication of his memoir as a book in 1865. It is considered the first White House memoir. A free man, Jennings bought a lot and built a house at 1804 L Street, NW. He had reunited with his children, and his son John lived with him. His daughter Mary lived next door with her two children. His sons Franklin and William also lived in the area. After Desdemona's death, Jennings married a third time in 1870 to Amelia Dorsey. He died in northwest Washington, D.C., at the age of 75 in 1874. He was buried at
Columbian Harmony Cemetery in D.C. When that cemetery closed in 1959, the remains of those buried there were reinterred at
National Harmony Memorial Park in
Landover, Maryland. However, Jennings's remains (along with others unclaimed by family members) were lost in this process. In his will, Jennings left his family his house and property in northwest Washington. ==Works==