The actor, who plays werewolf Alcide Herveaux in the show, told Metro that he has always been drawn to more edgy acting jobs.
"I've always gravitated to challenging projects," he said. "It's interesting now that the things pushing boundaries are shows on cable TV, whereas film has become more conservative."
Manganiello said of True Blood: "It's the sexiest show ever made. It combines great humour with heartfelt drama and a level of kinkiness that's unmatched. Aside from that, it's smart and well written.
"It's about more than vampires and werewolves but that, and the sex and blood and shock value, makes for a good time."
> Joe Manganiello: 'We joke about nudity on True Blood'
> Best TV Vampires: Friday Fiver
He added: "Of all the things you can become recognised for I'm very happy it's this show. A lot of the things I did in drama school and theatre have been pretty out there and racy, which prepared me for this show.
"I shaved my head at drama school and pulled my teeth out for a role. I like to do things to get the heart racing. I did an Off-Broadway show that involved full frontal nudity."
Manganiello's co-star Anna Paquin once described True Blood as "full on sexy", adding that it includes "lots of weird, kinky vampire sex and weird, kinky mortal sex".
> True Blood casting Alcide's father?
Watch a clip from Season 4 of True Blood below: