Kennedy originally moved to Brunton Park on a one-month loan deal last month but he will now see out the 2014/2015 campaign with the Cumbrians.
The 28 year-old has made seven appearances so far for Carlisle, scoring twice, including the match-winner against Dagenham & Redbridge last Saturday.
Kennedy has also scored twice for the Bantams this season after featuring twenty-six times for Phil Parkinson's men before his loan move north.