Henson was part of Wales' 2005 Six Nations Grand Slam team coached by Ruddock, kicking a famous match-winning penalty against England.
The back, 35, has returned to Wales for the first time since 2012 to play for the region Ruddock coached in 2003-04.
"Hopefully he can play, but also become the leadership figure at the Dragons I am sure he is capable of at this stage of his career," Ruddock said.
"He would still be very ambitious and want to prove he can still perform at the very highest level.
"I hope Gavin could reflect on his career, on what has worked for him and what hasn't.
"Some of those experiences that have been positive for him hopefully he can use those to help shape the way forward in the Dragons."
Henson last played in Welsh domestic rugby for Cardiff Blues in 2012, after making his name with Swansea and the Ospreys between 2000 and 2009.
In between, Henson - who won 33 caps for Wales and one for the British and Irish Lions - has played club rugby for Saracens, Toulon, London Welsh, Bath and Bristol.
Ruddock's one season in charge of the Dragons was their most successful, and he hopes the Welsh Rugby Union's takeover of the region this summer will pay dividends.
"It was definitely time for a change and probably long overdue," Ruddock added.
"Since my time there the Dragons have huffed and puffed and not lived up to the standards we thought they were capable of.
"It sounds like the right things are being done with the [new] pitch coming in already, that sounds like a fantastic move."
The Dragons also have a new head coach in former Ireland hooker Bernard Jackman.
"Bernard is a good young coach who had cut his teeth in France and in the All-Ireland League where I am currently coaching with Lansdowne," said Ruddock.
"He was with Clontarf and did well there.
"He's worked under a lot of good coaches during his time and would have had a good understanding of the game."
Ruddock's son Rhys captained Ireland on their summer tour against USA and Japan, while his older son Ciaran is captain of All-Ireland side St Mary's College.
"That was a big day for him and the family to see Rhys captain Ireland," said Ruddock, whose wife Bernadette is Irish.
"Ciaran has just been made captain where he will be playing against my team, so that has become all of a sudden an even tougher job!"
After coaching stints in Wales, England and Ireland with international, regional, provincial and age-grade sides, Ruddock is settled in Dublin, guiding Lansdowne in the All-Ireland League and working part-time in private business.
"I have learned a lot of lessons along the way, good and bad and am trying to help a lot of youngsters in Lansdowne," said Ruddock.
"At 58 next month, I still think I am in my prime!
"What I love about the All-Ireland League is that you can go to places like Young Munster in Limerick and Cork Constitution and there is still that Munster v Leinster feel to it.
"There is relegation, play-offs, so everything is very competitive.
"We have won it a few times and provided some players who have gone onto get a professional contracts."
Mike Ruddock believes Gavin Henson can be a success at Newport Gwent Dragons.