Indeed he was! He was also quite outspoken against the treatment of Native Americans (at least, relative to his time) having spent a significant amount of time

Indeed he was! He was also quite outspoken against the treatment of Native Americans (at least, relative to his time) having spent a significant amount of time living among the Cherokee. This won him quite a few enemies, as the "Indian problem" was a pretty significant issue in the nascent Republic of Texas. He was strongly opposed to Texas secession and gave one of his most famous speeches in opposition to it. For anyone interested, T. R. Fehrenbach's "Lone Star" is a great history of Texas and of Sam Houston (among many other colorful characters).