FM 149 was created on April 20, 1945 as a short spur between Anderson and Richards inside Grimes County. Later that year, it was extended twice, to the Montgomery County line on June 6, 1945 and to Deckers Prairie ten days later. The designation was extended down the Tomball Road to US 75 (later  I-45) in Houston on July 22, 1949.
FM 149 originated as a brief connection between Anderson and Richards in Grimes County on April 20, 1945. It was subsequently expanded to reach the Montgomery County line by June 6, 1945, and then further extended to Deckers Prairie ten days later. The designation eventually reached US 75 (later I-45) in Houston by July 22, 1949.