A running back from UNI doesn't typically run for 199 yards against Iowa State. But don't tell that to Number 7.
"I don't know if we've ever had anybody with his size and his ability at UNI and you know, I've been here quite a while," said offensive coordinator Bill Salmon.
It's not just talent with David - he's known for his hard work on the weights.
"You go in the weightroom with him, he's one of the strongest guys in the room. He comes early and stays late," said head coach Mark Farley
The running back also spent the summer as a janitor at the school's department of residence.
"He had to stay and find a way to pay for rent and those types of things this summer and he did that by getting a job at the department of residence," Farley said.
It wasn't exactly the most glamorous job for the team's star player.
"Getting up at 5:30, get to work at 6, clock in, then we go to one of the dorms around here, just go through each floor," Johnson said.
"Drains are a pain. Kids throw everything down the drain, they just get plugged up. They stink, and they're dirty," said co-worker Phil Chien.
For a player who's put in the hard work, he also learned what it's like to put in the dirty work.
"You should see some of the hair with toothpaste grimed up and everything, it wasn't a pretty sight," Johnson said.
Right now both kinds of work are paying off. Johnson is 2nd in the FCS in rushing and leads the team with five touchdowns through only two games.
"I've seen a lot, and there's only but one David Johnson right now," said Salmon.
Whether its a clogged running lane, or a clogged sink drain, there's not much David can't get through.