Powell announced last month he will leave Tigers at the end of this season.
Though he denied having a new job lined up, he was immediately linked with the big-spending Cheshire club.
Warrington revealed during pre-season their team boss Steve Price will leave when his contract expires this autumn.
Powell, who is a former Leeds player and also coached Rhinos and Featherstone Rovers, joined Tigers in 2013 and guided them to top spot in Betfred Super League four years later.
He has signed a three-year contract with Warrington.
In a statement released by the Wolves on Tuesday, Powell said: “Warrington is an outstanding club with a rich history and the opportunity to coach the club from 2022 onwards is a very special one. I’m looking forward to the challenge.
“Wherever I’ve been as a coach I’ve fully embedded myself into the club and the town.
"I think it is really important as a coach that you do that and I’m looking forward to meeting all the Warrington fans next season."
He added: “My coaching philosophy is to support players to achieve special things and I think everyone knows and can see what I like to do with my players and teams.
“I feel like I’m moving from one special club to another. I think it’s important to get it out in the open now so I can focus on the year ahead and there’s certainty from both sides at this stage.
"Hopefully there’ll be an excitement at Warrington and an excitement at Castleford that I can finish off there in a really positive way this season.”
Warrington chairman Stuart Middleton said: “After the completion of a thorough process we believe Daryl is the best man to take the club forward in 2022 and beyond.
“His coaching philosophy and the brand of rugby league he promotes is something that really appealed to us.
"The impact he has had at Castleford is very impressive, taking them from 12th to league leaders in four years in a playing manner that was unrivalled in Super League.
“His ability to improve players was also an attraction; under his guidance he’s helped to develop three players into Men of Steel.
"We’ve got an exciting crop of youngsters emerging so we look forward to seeing how he helps shape and develop their game.”