Pearson, 27, who played 40 league games for the Hatters in 2020-21, has signed a three-year deal with the club having an option of a further year's extension.
On the signing, Head of Football Operations Leigh Bromby said: “We’re really happy to add Matty to our squad. He’s a good character, he knows the division and is a leader in the dressing room.
“We want players at this club who are ambitious, that lead by example and that will fight for us; Matty is all of these.
“He has been playing regularly for Luton in the Sky Bet Championship and will certainly add a lot to our squad.”
Terriers head coach Carlos Corberán added: “Matty has good experience in the Championship and has played many minutes over the last two seasons, which shows he’s robust and able to deal with high physical demands.
“He’s a big presence, good in the air, strong in the tackle, and what really stands out is his competitive character.
“He gives us extra versatility in defence as he can play as a right centre-back in a three or just with the left centre-back in a back four. We look forward to working with him.”
Pearson will help step into the breach following the exits of senior defenders Richard Stearman and Tommy Elphick, who were recently freed by the club.
The one-time Halifax defender made his name at Accrington, with his performances earning him a move to Barnsley in the summer of 2017.
But after just one season at Oakwell, where he struggled to establish himself, he moved to Luton and developed under the tutelage of Nathan Jones to take his career onto new heights.