SH 128 was originally designated on May 21, 1927 along a route from
Sinton northeast to the Victoria County line. On October 11, 1927, it was extended south to
Robstown and numbered SH 128. On March 19, 1928, it was extended north to
Victoria. On June 24, 1931, it had been extended west to
Alice, replacing a portion of
SH 12A. On September 19, 1933, it was extended north to
Hallettsville. On July 15, 1935, the section from Victoria to Hallettsville was cancelled (as it was not built yet). On September 26, 1935, the section from Victoria to Hallettsville was restored as part of the lateral road program, and construction started on that section. On November 24, 1936, the entire route became part of
SH 44.
SH 128 was then designated on the current
SH 237 from
La Grange northeast to
US 290 near
Carmine, replacing a portion of
SH 72. This was renumbered as
SH 237 on December 22, 1936, presumably to avoid confusion with the just cancelled SH 128. The current route was originally designated on May 7, 1948 as
Farm to Market Road 781 and ran from the state line to FM 703. The highway was signed, but not officially designated, concurrently as SH 128 beginning on March 30, 1955, "for guidance of traveling public" to correspond with New Mexico State Highway 128 (which was renumbered from NM 256 to NM 128 that day; FM 703 was signed but not designated as part of SH 115 in October 1952). ==Major intersections==