Flannery knew President Abraham Lincoln and was at Ford's Theatre the night of the assassination. Shortly after Lincoln's death, Washingtonians chose to erect a memorial honoring the slain president. Many designs were submitted to the monument planning committee, but Flannery's model was unanimously chosen. The committee called his design the "most spirited" and "an excellent likeness." The memorial was dedicated on April 15, 1868, the third anniversary of Lincoln's death. Flannery's statue is the only statue of Lincoln created by someone who knew him.