Moriarty missed the opening game of the season through suspension, but is called up as Head Coach Bernard Jackman makes five changes to his starting line-up for the visit of the South Africans.
A new-look front row sees prop Brok Harris and hooker Elliot Dee named, as they pack down with Leon Brown.
Lock Matthew Screech is named in the second row alongside captain Cory Hill.
The final change is at fly half where Josh Lewis will make his first Guinness PRO14 start, replacing the injured Gavin Henson.
Fly half Arwel Robson is named among the replacements.
Jackman said: “The players have trained exceptionally hard all week and how we respond to last Saturday’s game with Benetton Rugby will be a good test of our character.
“We want to put our best foot forward and show we are much better than we were in the opening round.
“We’re all looking forward to seeing Ross (Moriarty) in a Dragons jersey,” he added.
“Ross has a real edge to his game and is a good leader for us already. He will give us a boost, but it’s going to take a 23-man performance to make sure we get the right result.”
Dragons (v Isuzu Southern Kings): Jordan Williams, Dafydd Howells, Tyler Morgan, Jack Dixon, Hallam Amos, Josh Lewis, Rhodri Williams; Brok Harris, Elliot Dee, Leon Brown, Matthew Screech, Cory Hill (c), Ollie Griffiths, Aaron Wainwright, Ross Moriarty
Replacements: Richard Hibbard, Ryan Bevington, Lloyd Fairbrother, Brandon Nansen, Huw Taylor, Tavis Knoyle, Arwel Robson, Adam Warren