Following the end of the war, Davis became a member of the 1866 Texas Constitutional Convention. He supported the rights of freed slaves and urged the division of Texas into several Republican- controlled states.
In 1869, he was narrowly elected governor against Andrew Jackson Hamilton, a Unionist Democrat. As a Radical Republican during Reconstruction, his term in office was controversial. On July 22, 1870, the Texas State Police came into being to combat crime statewide in Texas. It worked against racially based crimes, and included black police officers, which caused protest from former slaveowners (and future segregationists). Davis created the “State Guard of Texas” and the “Reserve Militia,” which were forerunners of the Texas National Guard.
Davis’ government was marked by a commitment to the civil rights of African Americans. One of his protégés was Norris Wright Cuney of Galveston, who continued the struggle for equality until his own death in 1896 and is honored as one of the important figures in Texas and American black history. Though Davis was highly unpopular among former Confederates, and most material written about him for many years was unfavorable, he was considered to have been a hero for the Union Army. He also gained the respect and friendship of Spanish-speaking residents on the Rio Grande frontier.
In 1873, Davis was defeated for reelection by Democrat Richard Coke (42,633 votes to 85,549 votes) in an election marked by irregularities. Davis contested the results and refused to leave his office on the ground floor of the Capitol. Democratic lawmakers and Governor-elect Coke reportedly had to climb ladders to the Capitol’s second story where the legislature convened. When President Grant refused to send troops to the defeated governor’s rescue, Davis reluctantly left the capital in January 1874. He locked the door to the governor’s office and took the key, forcing Coke’s supporters to break in with an axe. John Henninger Reagan helped to oust him after he tried to stay in office beyond the end of his term. Davis was the last Republican governor of Texas until Republican Bill Clements defeated the Democrat John Luke Hill in 1978 and assumed the governorship the following January, 105 years after Davis vacated the office.
Following his defeat, Davis was nominated to be collector of customs at Galveston but declined the appointment because he disliked U.S. President Rutherford B. Hayes. He ran for governor again in 1880 but was soundly defeated. His name was placed in nomination for Vice President of the United States at the 1880 Republican National Convention, which met in Chicago and chose James A. Garfield as the standard-bearer. Had Davis succeeded, he might have wound up in the White House, as did Chester A. Arthur, the man who received the vice-presidential nomination that year. Davis lost an election for the United States House of Representatives in 1882.
After Democrats regained power in the state legislature, they passed laws making voter registration more difficult, such as requiring payment of poll taxes, which worked to disfranchise blacks, Mexican Americans and poor whites. They also instituted a white primary. In the 1890s, more than 100,000 blacks were voting but by 1906, only 5,000 managed to get through these barriers. As Texas became essentially a one-party state, the white primary excluded minorities from the political competitive process. They did not fully recover their constitutional rights until after enforcement under the Voting Rights Act of 1965. Edmund J. Davis died in 1883 and was given a war hero’s burial at the Texas State Cemetery in Austin. A large gravestone was placed in Davis’ honor by a brother. Davis was survived by his wife, the former Anne Elizabeth Britton (whose father, Forbes Britton, had been chief of staff to Texas Governor Sam Houston), and two sons: Britton (a West Point graduate and military officer), and Waters (an attorney and merchant in El Paso).