Howson, 25, joined the Canaries from Leeds in January 2012 and has made 60 appearances, scoring five times including a fine individual effort on the final day of last season at Manchester City.
Hughton - who brought in half-a-dozen new signings in the summer - has selected Howson in each of Norwich's 16 Premier League matches so far this season, and is delighted with the midfielder's development as the Canaries have slowly started to climb the table.
"A new contract comes in line with Jonny's form this season, which has seen him be a mainstay of the team and put in some impressive performances," Hughton said on the club's official website, www.canaries.co.uk.
"In the period of time that Jonny's been here, there's been progression in his influence in the team and in the matches, and we're delighted to be able to secure his services for the next four-and-a-half years."
Howson joins team-mates John Ruddy, the England goalkeeper, and club captain Sebastien Bassong in penning contract extensions to commit their long-term futures to the Norfolk club.
The former Leeds trainee hopes to build on his promising start to the 2013/2014 campaign. He said: "As soon as I found out there was an offer there I was very interested in getting it signed. I am very settled here and happy to sign.
"I have really enjoyed the season so far and have had a good run in the side. I just want that to continue, and obviously staying here longer gives me the chance to do that."
Norwich drew 1-1 with Swansea on Sunday to edge up into 14th place, five points clear of the relegation zone and head to bottom club Sunderland this weekend.
Club-record signing Ricky van Wolfswinkel could be involved at the Stadium of Light, having been sidelined since the end of October by a toe problem.
Winger Robert Snodgrass continues his recovery from a knee injury sustained in the build-up to the Newcastle match last month, and the Scotland international may well come back into contention for the festive fixtures against Fulham on Boxing Day and Manchester United.
"I am progressing nicely, but I don't want to put a timescale on it. I will leave it to the head physio to tell me when I am ready," Snodgrass said on the club's official website.
"We got it scanned and the outcome was four to six weeks, these things happen, but I am big enough to just work hard and look forward."
Snodgrass is confident he will rejoin a side now looking up the table after slowly building some positive results.
"I know the players are ready for the challenge ahead. I am sure the supporters have not been happy with some of the performances like at Manchester City and Liverpool, but we have also picked up some decent results and I think you can see every point is vital in this league."