When this film debuted in 1951, Mickey Rooney was not nearly as popular an actor in Hollywood as he'd been a decade earlier. And, so many of his previous films were nothing like "My Outlaw Brother" but were more slices of an idealized American life--minor love stories involving his Andy Hardy character or superficial musicals. Here, however, he is inexplicably in an independent B-western--a HUGE change of pace from the usual fancy MGM pieces he appeared in at the time. Now this is not a bad thing--as it did offer a nice change of pace and a chance to see him in a more gritty sort of film.
The movie begins with an Easterner (Rooney) showing up out West...unprepared and totally out of place. Despite this, he manages to find a friend in a local Texas Ranger (Robert Preston) who looks out for him. However, the Ranger is surprised to learn that his new friend, though quite likable, might just be the brother of a local outlaw who is wanted on both sides of the border. So, when this greenhorn travels into Mexico to find his brother, the Ranger tags along. What's next? See the film.
For a B-western, this is better than normal. Some better than average acting, a decent script and nice production values make this quite satisfying and worth your time--even with the odd ending where Rooney's character seems amazingly ambivalent with the way things ended up by the conclusion.