(Seibels) In 1861, during the American Civil War, Walker was conscripted in the Confederate Army and was sent to Morris Island as part of the Palmetto Guard.
For the remainder of the war he served as a civilian draftsman to the Confederate Engineers Corps and made maps and drawings of Charleston's defenses.
After the Civil War, Walker moved to Baltimore, where he produced small paintings of the "Old South" to sell as tourist souvenirs.
He is best known for his paintings depicting the lives of poor black emancipated slaves, especially sharecroppers in the post-Reconstruction American South.
Walker continued painting until his death on January 3, 1921, in Charleston, where he is buried in the family plot at Magnolia Cemetery.