Commander of the Army might also be a stretch. The Republic of Texas army was little more than a mob and Houston was barely in control of them.
This is not to say I dislike Houston. I love him. But he got all of his early positions from his relationship to Andrew Jackson and he got lucky later on.
I think his best moment was when he fought secession. He knew it would be a disaster and although he prized his reputation, he was willing to sacrifice it for what he believed. I'm not a southern apologist, but neither am I the alternative. With John Brown fresh on their minds, the idea of an abolitionist president caused real and legitimate terror in the south, and although Lincoln was no extremist, he couldn't just go on TV and calm their fears. And the raising of troops to invade the South was a provocative act that needlessly forced Texas over the edge. It was an era in which cooler heads were unable to prevail, even though Houston tried.