This young man is identified as Vance A. Smith, S.M.B.A., 1918. The photographer's stamp is Jno. Carter of Luling, Texas.
To begin with, my theory was that the S.M.B.A. might refer to the San Marcos Baptist Academy. This looks like a school boy to me, somewhere between the age of 12 and 16. A check of Ancestry provided two public family trees that help tie down the identification.
Vance Allen Smith was born January 22, 1903, in Gonzales, Texas. His parents are William A. and Ella Mae Smith and in 1920 the three are living in Gonzales.
By 1930, the family has relocated to Bastrop, Texas, and William is a druggist, with Vance working as a clerk in the drugstore. Vance has a young wife (15 to his 25) named Ruby J.
The person who posted the family tree has also posted a photo of "Maw Maw and Paw Paw" and the man in that photo is undeniably the same person shown here.
In the family tree, Vance's wife is shown as Effie Geisert and a child named Ruby J is listed. I was unable to find a marriage record, but the 1930 census definitely shows the daughter-in-law of William Smith as Ruby J. It could be the census taker muddled the name of the wife and a child that failed to get enumerated. Hard to say, but there is enough information here to begin a search - even with the last name of Smith.