It's not that any contribution is inherently unworthy in and of itself, nor the whole, but it doesn't take long before this 1938 film starts to make an impression as a more frivolous type of western. The editing, persistent use of flashbacks and narrated fragments of story, Hugo Riesenfeld's simplistic but highly dramatic score, and the presence of singing cowboys all work within even the first ten minutes to paint 'King of the Sierras' as a title built for uncomplicated amusement rather than earnest storytelling. Meaning no offense to young Harry Harvey Jr., the prominent inclusion of a child quite emphasizes the point. Some sage words imparted from Uncle Hank (Hobart Bosworth) and our first glimpses of the cinematography portend a stirring, classic western saga, albeit one quite centering wild horses; this swiftly transitions to Uncle Hank telling pre-teen Tommy about "El Diablo," reminding of those old "talking" Mickey Mouse dolls that would play cassettes of Mickey relating a short story, and many subsequent instances of the camerawork are rather static, artless, and dull.
There's not necessarily anything wrong with any of this. Movies geared for younger audiences, or movies that are light and fluffy affairs, can be perfectly enjoyable. It's just that the approach here catches one off guard compared to other contemporary flicks generally, other westerns more particularly (even those of singing stars Roy Rogers or Gene Autry), and most specifically other westerns starring Rex the Wonder Horse, or silent westerns that had populated the silver screen in the past. If you step into this feature anticipating another fully sincere western lark a la Tom Mix or William S. Hart, you're in for a surprise. Still, be all that as it may, it's hardly that there is no value here. I don't think the framing or narration serve the title well as they inculcate a sense of triviality if not outright childishness - yet the underlying plot is solid in and of itself. Though rough around the edges, some of the cinematography is most splendid; the landscapes and the equines are equally gorgeous. Those stunts that are employed look terrific, a fine credit to the humans and horses alike (although necessarily raising questions about humane treatment and animal labor).
Maybe at least in part it comes down to a matter of personal preference; a lighthearted little nothing is fine, I suppose, but I was expecting and would have rather had a serious dramatic piece. The more the tale of the wild horses is sidelined for focus on Uncle Hank, Tommy, and Pete, including kitschy attempts at humor, the less interesting this is in my opinion. Then again, there's also just the problem here of how the picture was put together; in the worst instances of editing and camerawork it comes off as all but completely amateurish and unskilled. In every capacity a more thoughtful, careful, straightforward slice of cinema would have been far superior. It's not that 'King of the Sierras' is downright bad, but its best elements are sadly, significantly undercut by its worst ones; case in point, when a major dramatic beat rolls around in the story within a story at about the 45-minute mark, it feels like it comes out of nowhere, with an abrupt tonal shift no less. The result is a film that is overall no more than baseline entertaining - it's "okay," but it had the potential to have been "very good," and as it is I wonder if I'm not being too generous in my assessment. I'm glad for those who get more out of this than I do; if you do have the opportunity to watch and are open to the approach on hand, it's a suitable way to pass a lazy hour. Definitely don't go out of your way for it, however, and be aware of those ways in which the movie falls short.
