Johnson signed for the Rams ahead of the 2015 season following an impressive spell with Swinton Lions, but was sidelined with injury for almost the entirety of his debut campaign.
He will now spend the next month under former Rams player, and current Hawks head coach, Matt Bramald, where he will aim to get some much-needed first team experience under his belt.
Rams head coach Glenn Morrison said: “Zach is needing regular game time to get his fitness up to speed, and to work on things we have highlighted through pre-season games he has played in.
“This month-long loan is perfect for him to be able to do that close to home, where I can keep close watch over him.
“It also benefits Hunslet, who are needing a quality player in that position, and we believe it will be a beneficial arrangement for all three parties.”
Johnson could make his debut for Hunslet in their League One season opener against Rochdale Hornets on Sunday.