Mario Valentin Gallegos Jr. (September 8, 1950 – October 16, 2012)[1] was an American Democratic politician in the U.S. state of Texas.

[7] Nevertheless, Gallegos was sworn in as Governor for one day on May 5, 2007, in a Texas tradition honoring the Senate President Pro Tem.

[8] Gallegos attended the University of Houston–Downtown (UHD) where he received a Bachelor of Arts degree in social sciences in 2001.

His liver donor was 16-year-old Robby Joe Trevino Jr. of Fort Worth, Texas who died unexpectedly from cardiomyopathy.

[11] Gallegos installed a hospital bed in the office of the sergeant-at-arms at the capitol building so that he could be nearby to prevent discussion of a bill requiring voter identification, against doctors' orders.