Houston's had more than a few interesting mayors who could have gone on to higher office.
-Oscar F. Holcombe was mayor for over two cumulative decades and in five separate non-consecutive administrations, from the Twenties to the Fifties. Millionaire land investor, opponent of integration, but stood up to the Klan in the '20s.
-Roy Hofheinz was preceded and succeeded by Holcombe from 1953 to 1956. Responsible for the creation of the Colt .45s baseball team (look, this is Texas, okay?) and the Astrodome (where he lived for several years, by the way), campaign manager for Lyndon Johnson, and oversaw much desegregation, as in this anecdote:
Black community leaders asked him to desegregate libraries in Houston. He agreed, but first he called in representatives of press, radio, and television and asked that they hold off any news about the upcoming change until librarians could determine how the mixing of races in their buildings would work. When word finally got around that black children and adults were going to “white libraries,” a woman, prominent in Houston society, complained to the mayor: “I won’t let my children sit by black children at the library,” she angrily told Hofheinz. “I don’t know what they’d catch!” Hofheinz solemnly replied, “Maybe tolerance.”
Also once arrested two City Council members for boycotting a meeting, then got involved in a long fight with the Council which culminated in his calling for election a year early to try to get his City Council out, an act which backfired when Holcombe came out of retirement.
-Lewis Cutrer, who succeeded Holcombe's last term. Created Lake Livingston and Houston Intercontinental, as well as continuing desegregation. He was defeated in 1963 by:
-Louie Welch, mayor for a decade. Known for quick quips, perhaps most notably floating "shoot the queers" as a solution to the AIDS crisis. While mayor in the Sixties, presided over a violent standoff with mostly-black TSU students. George H.W. Bush met with him in 1965 to see if he was running for the House seat that Bush eventually won, saying “Before I run, I want to know if you have any ambitions. Because if you do, I can’t beat you.” Possibly associated with organized crime, definitely sketchily funded in his second mayoral bid. Came out of retirement in the Eighties to run against Kathy Whitmire due to her support of job protection for gay city employees, a race in which he made the aforementioned quip, and lost.
-Kathy Whitmire, mayor from 1982 to 1992. Fought corruption and discrimination, making significant reforms in garbage collection and public transportation, an issue on which she was defeated. Fought to break the power of the "good ol' boys". First mayor to appoint African-American police chief.
-Bob Lanier. Defeated Whitmire in 1991, largely due to his opposition to Whitmire's proposed monorail. Noted builder, oversaw affirmative action and a sizable drop in crime. Term limits established to keep him from running again in 1997, when Lee Brown was elected.
-Lee P. Brown. First black mayor of Houston, police chief under Whitmire. Oversaw light rail, revitalized downtown, advanced affirmative action and e-government. Reconstruction of downtown led to challenge by city councilman Orlando Sanchez, who lost despite endorsements from President Bush and the police officers' union. Also: Bill Clinton's drug czar. Also headed Atlanta and New York City police departments. Succeeded by:
-Bill White. Worked to host refugees from Hurricane Katrina, fought pollution. Also responsible for debatably-helpful possibly-deadly anti-traffic program SafeClear, and installed many red-light cameras. Tried to close The Center Serving Persons with Mental Retardation due to issue regarding illegal lease. Ran for Governor in 2010.
-Annise Parker. One of the first openly gay mayors of a major American city. Fought for Houston Equal Rights Ordinance, unfortunately defeated in 2015, largely due to transphobia. That same year, our current mayor was elected:
-Sylvester Turner. Staunch supporter of HERO, after opposing some previous pro-LGBT laws in his Texas Senate career (I think he's genuinely changed his opinion in the last decade, but it's hard to say what's really going on there). Pro-choice and fought for grand jury reform. First ran for mayor against Lanier in 1991.