The 30-year-old former Hull, Castleford and Wakefield scrum-half has been in outstanding form for Paul Anderson's side this season, fuelling a strong title bid.
Brough joined the Giants in 2010 and could now see out his career with the West Yorkshire club.
Brough said: "I am immensely proud to captain this club and I am certain we have some great days ahead of us.
"My family is very settled here, it's a good club off the field and the lads really are a close group.
"I probably could have moved on but why would I want to?"
Brough has long been one of Britain's most potent half-backs and showed his talent on the grand stage with a superb display in Hull's 2005 Challenge Cup win.
Yet it is not until settling at the Giants that he has consistently excelled.
His performances this season - which have yielded 237 points in Super League - have helped his side establish a one-point lead the top of the table with five regular-season rounds remaining.
Brough said: "I am happy with my form so far and feel that maturity is now bringing the best out of me, for which I have to thank the family and some key people at the club who have always had faith in me.
"I really hope I can play a big part in the team going forward to repay this deal with silverware for the fans and chairman.
"At the end of this deal I might be able to squeeze some more games out but it is fair to say it's obviously my last major contract and I am just delighted that it's going to be as a Giant."
Head coach Anderson added: "Danny's form is clear for everyone to see this year.
"I enjoy working with him as captain and it's great news that he is here for the long haul.
"I think we both share common goals regarding what we can achieve at this club and having a half-back of Danny's quality is a huge boost to us."
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