Johnson said education was a big factor in his commitment to SMU.
"First of all, I talked a lot with (wide receivers coach Jason) Phillips about it," Johnson said. "Basically he told me that the graduating players get jobs here and there."
"It's a good diploma to have when you graduate."
"(Also) it's close to home. But I like their football team. It is just a good group to be on."
Johnson says that Phillips has done a good job building a relationship with him.
"In the time that I've known Coach Phillips our relationship has grown," Johnson said. "I'm sure it'll get even better after I start working with him.
"He came out to a scrimmage before our spring game and we've talked probably once a week since then. I talked to him this morning before I made the commitment."
Johnson, who held offers from Southern Illinois and Central Oklahoma, chose to commit at the beginning of the summer "because (he) could see (himself) going there."
"I just wanted to commit and watch them this year, watch them progress, watch the season how (June Jones) handles everything. The way he does it, I like it," Johnson said.
The rising senior plans on attending a number of SMU games in the fall.
Johnson stands at six-feet tall and he thinks this size will allow to line up both outside and in the slot for the Mustangs.
"Basically, I'll line up either in the slot or the outside, whichever one would help the team," Johnson said. "Footwork and route running separates me from other players.
"For one, I'm not too short but I'm not too tall. I think that gives me a boost because I can play the outside and get around the guy but I can also play the slot because I have the footwork for it. And I can maneuver through the linebackers when I get inside."
Johnson still knows there are areas he needs to improve in this next season before moving up to the college level.
"Well, I know I need to improve strength-wise and get stronger. One thing I'm curious about is getting out of my break earlier and getting real separation," Johnson said. "I mean, I get separation now but it's not where I want it to be so I need to work on that."
As a rising senior, Johnson hopes to step into a leadership role for South Oak Cliff.
"I think my role will be to keep the team together because there will be times when we have our differences but we can stick together," Johnson said.