Johnston steps into the newly-created position with Worcester bottom of the Aviva Premiership and seven points off the pace in Pool 1 of the Amlin Challenge Cup but Ryan reckons his appointment is a major step in the right direction.
"I think it is a massive statement of intent from the club. Nick is renowned as one of the best around, so it was an opportunity to bring him in and create world-class systems, which is a radical shift from where we've been," said Ryan.
"It's about developing our own players and Nick's record at Northampton and Sale is second to none, so for us to be able to get him is a magnificent coup considering the amount of people who were chasing him."
Johnston spent more than five years at Franklin's Gardens having moved to the East Midlands from Sale Sharks in 2008. He helped the Saints reach six finals in six seasons, including an Amlin Challenge Cup win over Bourgoin in 2009 and a runners up spot in the Heineken Cup two years later.
He now has his sights set on similar success with Worcester as they look to kick on having finally picked up their first win of the season against Cardiff Blues in the LV= Cup a week-and-a-half ago.
"Having left the Saints after several wonderful years at the club, I needed a new challenge. This is a tremendous challenge and I am excited by the vision which this club clearly has," said Johnston, who joins Carl Hogg, Shane Howarth, Simon Cross and Ceri Jones on the Warriors coaching staff.
"I have known Dean (Ryan) for many years and I am a great admirer of everything he has done in the world of rugby. This is exactly the challenge I've been looking for and I cannot wait to get started."
Johnston's time at Worcester ironically begins against both his former sides, with the Warriors returning to Premiership action at Sale on Friday night before hosting Northampton a week later.
They then get their Amlin Challenge Cup campaign back underway with a double header with 2012 winners Biarritz Olympique knowing only successive wins will give them a realistic hope of reaching the last eight.