By the First Reconstruction Act of March 2, 1867, the United States Congress divided the defeated South, already restored under presidential Reconstruction, into five military districts, of which Louisiana and Texas, under Gen. Philip Henry Sheridan at New Orleans, constituted the Fifth Military District. For readmission to the Union under the congressional plan, each unreconstructed state was required to ratify the Fourteenth Amendment and elect by universal manhood suffrage (excluding prewar officeholders who had served the Confederacy) a convention to write a constitution acceptable both to the state's voters and the Congress. A Second Reconstruction Act of March 23 added procedural details, particularly regarding voter registration, and required that a majority of a state's voters approve the holding of a convention. And a Third Reconstruction Act of July 19 further clarified procedure and empowered district commanders such as Sheridan to remove state officials impeding Reconstruction. These acts of 1867—representing to some extent a collusion of Republican congressional leaders and the War Department, plus other influences such as violence and racial hostility—provided the context within which the commanders of the Fifth Military District and other districts operated. Sheridan and his subordinate, Gen. Charles Griffin, who headed military affairs in Texas, immediately interpreted the first two Reconstruction acts in such a manner as to proceed with what would be clearly authorized only in the third act. Sheridan relieved Louisiana officials in March; and in April Griffin initiated a county-by-county cataloging of acceptable potential Texas officeholders. On July 30 Sheridan replaced Texas governor James W. Throckmorton with Elisha Marshall Pease, who only recently had helped found the state's Republican party. Griffin died of yellow fever in Galveston on September 15, but his successor, Gen. Joseph J. Reynolds, a close friend of army general in chief Ulysses S. Grant, took an equally dim view of former pro-Confederates and during the next two months replaced more than 500 county officials. In late November, President Andrew Johnson replaced Sheridan with Gen. Winfield Scott Hancock, a Democrat, who subsequently protested the removals. Grant, however, advised against reversing Reynolds's decisions.
Hancock became an instant favorite of the district's conservatives, but he allowed the election of the Constitutional Convention of 1868–69 under a registration that had been controlled by Reynolds, despite allegations that the military-appointed local registration boards had acted illegally and unfairly in disfranchising about 10,000 former Confederates. In March 1868, after serving only four months, Hancock was granted a transfer, and Gen. Robert C. Buchanan, the senior officer in Louisiana, succeeded him.
In June, after fulfilling the conditions of the congressional Reconstruction acts, Louisiana gained readmission to the Union, leaving only Texas in the Fifth Military District under Reynolds. Reynolds served until Grant was elected president in November, when Johnson replaced him with Gen. Edward R. S. Canby, whom in turn Grant replaced with Reynolds upon Grant's inauguration in March 1869. Reynolds, opposing further disfranchisement or division of the state, initially favored moderate Texas Republicans, who supported the election of former provisional governor Andrew Jackson Hamilton for governor. By midsummer, however, Reynolds turned on the moderates, either for personal reasons because of their failure to back him for a United States Senate seat, or because of the moderate Republicans' flirtation with white Democrats, whom they needed due to the Radical Republican control of the black vote. At Reynolds's suggestion, Grant set the gubernatorial election late in 1869, allowing Radical Republicans an extended period to organize, and he removed many of the Hamilton-Pease federal officeholders, replacing them with radicals, who supported the candidacy of Edmund Jackson Davis, recently president of the constitutional convention.
President Grant's action, plus that of Reynolds in removing state and local officeholders who backed the Hamilton-Pease faction, caused Governor Pease to resign on September 30. Reynolds declined to fill the position before the November election, in which Davis, with Reynolds's aid, won by a small margin. Reynolds called a session of the provisional legislature in February 1870 to apply for the readmission of Texas to the Union, a session that also elected the state's United States senators. He was a candidate for a short time before withdrawing his name. In April Texas was readmitted to the Union, and the Fifth Military District ceased to exist.