Gentlemen in the 1920's wore their hair longer on top and shorter on the sides. It was slicked back with greasy products to keep it off of the face and out of the way.
This young man has a very definite side part that is very much an important detail of this hairstyle. It is actually more off center and serves as the point where each side is combed slightly up and then back. There are no side burns but a full mustache was very popular. His white shirt has a collar that is flipped up toward the neck and a neck tie as well. A vest along with a dark colored wool suit jacket is worn to go to town. Pocket watches were common and were usually attached to a chain. This is an authentic sepia vintage photo to use as an example of how to get this sweet retro style.