The Pompey defender has become the first exit of the summer after moving to Elland Road for £500,000.
The 24-year-old inked a four-year deal as he joins up with Neil Warnock’s side.
Warnock stated Pearce is the ideal character for his side.
He said: ‘He’s just the type I look for when I go into a club at Championship level.
‘He fits the bill for everything - hunger, ability and so on. A lot of plusses.’