The full-back joined the club from Toulon on a national three-year dual contract, which will see the WRU foot the bill for 60 per cent of his contract.
Halfpenny has arrived as a replacement for Wales team-mate Liam Williams and could start at full-back on the opening weekend of the Pro 12.
The 28-year-old is well established as one of the world's best goalkickers but has been widely derided for failing to show the same attacking threat he demonstrated during his younger days.
Pivac says the three-time Lions tourist has spoken about working on rediscovering his edge and the Kiwi coach says he is excited about working with the new boy.
"He wants to improve his attacking game and get that back where it has been in the past," he said. "We are looking forward to that."