The 26-year-old back rower will share the role of vice-captain with Luke Robinson, providing back-up for new skipper Danny Brough, going into Saturday's opening game at St Helens.
"Brett's a player who commands the respect of everyone in the squad," said Giants coach Paul Anderson.
Ferres played the last seven matches of last season for Huddersfield after the club fast-tracked his transfer from the Tigers and is expected to be a key player for them in Super League XVIII.
"Brett Ferres is like another new signing for us," Anderson added. "We just threw him straight in last year. Now he's had a full season with us and knows what we're trying to achieve."