Henson was voted World Young Player of the Year in 2001 and made his Test debut against Japan the same year but then disappeared from the scene at a time Wales were persevering with Iestyn Harris, their big-money signing from rugby league.
The 23-year-old does not believe the two incidents were coincidental - and critics have suggested his talents lay wasting for three years.
Henry, who is now New Zealand coach, insists when he left the Wales set-up in 2002 Henson was still a raw talent needing development to fulfil his potential.
"When I was there he was very young and just finding his feet in the world," said Henry.
"I left in 2002 and he was an extremely young person in those days. We played him in a few minor internationals, if I remember rightly, and he had loads of natural talent and just had to bed down. That talent is now coming through."
Henson has always felt the expensive acquisition of Harris was a factor in his career slump.
Henson beat Clement Poitrenaud to win his IRB award in 2001 but then became increasingly frustrated.
Henson was languishing at Swansea as the club went into administration while Harris was given the chance to learn his rugby in the Test side.
"At the time, I had been named World Young Player of the Year - which was great - and I thought things were really going to kick off," Henson recalled.
"Then they signed Iestyn Harris, and that is probably where I lost out. They were always going to play him after spending that amount of money."
Henson is arguably one of Wales' most naturally gifted players and his performances in the Six Nations make him many experts' tip to partner Brian O'Driscoll in the British & Irish Lions midfield.
He is just one of a number of Wales players Henry expects to come up against in the summer when the Lions head to New Zealand.