After his daughter, Elizabeth Jennings, was forcibly removed from a "whites only" New York City streetcar in 1854, he organized a movement against racial segregation in public transit in the city. He helped arrange her legal defense, which included the young future President Chester Arthur, and won her case in 1855. Along with James McCune Smith and Rev. James W.C. Pennington, Jennings created the Legal Rights Association later in that year, a pioneering minority-rights organization. Its members organized additional challenges to discrimination and segregation, and gained legal representation to take cases to court. In 1865, a decade after Elizabeth Jennings won her case, New York City streetcar companies stopped practicing segregation.