Jones, 40, recently completed three seasons as head coach of RGC 1404 in the Welsh Premiership and will also guide the attack and look after the backs with Canterbury in the Mitre 10 Cup.
A 47-Test veteran, he made his Wales debut in 2001 after time in youth internationals at Under-18, U-19 and U-20 levels. He played his club rugby out of Llanelli and Scarlets. He assisted Namibia (pictured, left, with Namibia coach Phil Davies) at the 2019 Rugby World Cup.
Jones spent time in New Zealand in late-2019, returned to Wales for Christmas and is now back in Christchurch.
He told walesonline.co.uk, "I'm really excited. It's a huge opportunity and the welcome I have had in New Zealand has been fantastic.
"Without being disrespectful to other rugby clubs, the Crusaders are probably regarded as the best rugby organisation in the world. So for them to feel I can add value means a lot."
Jones ended his international career in 2009 and went straight into a coaching role with the Scarlets where he remained until 2015. After a season at Rotherham he had three years with RGC, including a Welsh Cup final win with the side in 2017.
He was part of the Wales Test set-up in 2012-13 when they won a Six Nations title.
However, he acknowledged the Crusaders appointment would be something different.
"I've spent a couple of weeks with them already and they are everything others have said they'd be, with open-minded people who are great off the pitch and smart on it.
"It's a unique environment and it's been a pleasure so far," he said.