Walls served as a delegate to the state constitutional convention of 1868, representing Alachua County. Later that year, he was elected to the Florida House of Representatives from Alachua, along with his friend, Henry Harmon, serving in Florida's first Reconstruction Legislature. When State Senator Horatio Jenkins was appointed to a county judgeship, Walls decided to run in the special election to succeed him. He was elected to the Alachua and Levy County district on December 29, 1868, and took office in January. Walls served as state senator for the 1869 and 1870 legislative session.
Congress
In 1870, Walls was nominated as the Republican candidate for Florida's sole at-large congressional seat after a contentious party convention. A moderate faction of mostly white carpetbaggers, led by U.S. Senator Thomas W. Osborn, supported the freedmanRobert Meacham, while the majority of black delegates were split between several more radical black candidates, including Walls. Walls won the nomination on the 11th ballot, after the other black candidates withdrew to prevent Meacham from winning. Walls went on to win the 1870 general election and serve in the 42nd Congress, but the vote was contested by Democrat Silas L. Niblack. The House Committee on Elections eventually unseated Walls after finding election irregularities. Walls ran for the at-large congressional seat again in the 1872 election and won. In office, Walls introduced bills to establish a national education fund and aid pensioners and Seminole War Veterans. In 1874, Walls ran for re-election to Congress in the newly redistricted 2nd district. Walls won the election but Democrat Jesse J. Finley, a former Confederate colonel, contested the results of the election. Finley was eventually declared the winner by the Democratic-controlled House of Representatives.
Return to state politics
Walls again sought the Republican nomination for the 2nd congressional district in 1876. After the black delegates split between Walls and another black candidate, the nomination went to a “white carpetbagger”, Horatio Bisbee. Walls instead ran for his old state senate seat, and served a four-year term. He lost re-election in 1880.
Legal career
Walls was admitted to the bar in Alachua County in April 1873. In June 1874, Walls formed a law partnership in Gainesville with Henry S. Harmon, who had been the first African-American admitted to the bar in Florida, and William U. Saunders. The next year Harmon and Saunders moved their legal practice to Tallahassee.
Later life
Leaving politics, Walls operated a successful farm in Alachua County until the disastrous freeze of 1894–95, which destroyed his crops. He took a teaching position as Farm Director of the State Normal and Industrial College for Colored Students, which much later would become Florida A&M University, in Tallahassee. After nearly a decade there, he died on May 5, 1905.