With this catalog of images taken by the Athletic Model Guild, I was able to identify the model in the photograph as Mike Powers, whose square jaw is unmistakable.
In the second row from the bottom of the catalog, Powers is taking a call from his agent.
Going forward, I'll add to the labels "AMG Index" whenever a catalog such as this appears in a post, for quick reference in the future. I see here at least two other models whose photographs have lingered for quite some time in my unidentified pile.
I must thank a generous fan of this blog for the catalog.