Howells, who was left out of work following the demise of the Warriors, was approached by the Blues to fill an organisational role at the Arms Park.
But Howells has opted to turn his back on his homeland after agreeing a two-year deal with the Parker Pen Shield semi-finalists.
"It's a positive challenge, something different," said Howells, who took temporary charge of Wales on their 2001 tour to Japan. "I had a fair offer from Cardiff, but this gives me more security and the chance to stay in coaching."
Howells takes a wealth of experience with him to Italy having coached both the Pontypridd and Cardiff club sides before last season's spell with the Warriors. Howells also formed a valuable part of Graham Henry's back-up staff during the New Zealander's time with Wales, including the record 10 game unbeaten run in 1999.
And having decided to take on his biggest challenge yet with the European minnows, Howells is hoping he can bring similar success to Leonessa.
"Italy will be different and exciting," he said. "I will have to learn a new language, get engrossed in a different culture and see if I'm good enough to coach a team in that environment.
"I hope to make a big impact on Italian rugby."