At 23-years-old, Smith is one of the younger players in the Vale side, and Legge has emphasised how much he has grown as a player since his arrival at the club.
Smith and Legge have started every game together in the league so far this season, and the defender believes his experience at the back of a young defence has played a part in Smith's development as a player.
The 34-year-old claims that Smith may not have been the most confident player in the squad upon his arrival but has since became one of the natural leaders within the side.
James Gibbons has also been an integral part of that Vale side this season and at 21-years-old he is also one of the younger players in the squad. However, Legge has described how Gibbons' maturity is something of a more experienced player.
He said: "Confidence is key, I think when I first come in to the club, even though he'd played quite a few games for the club, I think at times the confidence wasn't there, but he's definitely grown as a player.
"I don't want to sound too big-headed but I think I've played a part in that, and some of the other mature players have played a part in that as well, and I think the more he plays with us I think he's just going to get better and better. He's been talking a lot more over the last 12 months, he's a real leader at his age.
"Gibbo [James Gibbons] is the same, for a young player he talks a lot, and that's one thing that sometimes young players get scared to do because they're with the first team, but with Gibbo he's got an old head on young shoulders."
The Valiants return to Vale Park on Saturday where they will hope to extend their unbeaten league run at home to seven games, yet Legge stresses that they cannot rely solely on home form.
The centre-half has admitted how important it is to make Vale Park a fortress, but and improvement in away form is absolutely key.
One main aspect the Vale need to improve on is clean sheets admits Legge, the side have only kept one so far this term and the centre-half says he would have expected more at this stage of the campaign.
He said: "We had a lot a lot of clean sheets last season and we've only got one this season, and for me personally I expect us to have a lot more than one clean sheet so that's something we need to work on.
"Obviously our home record is very good, but it's something we can't rely on this year. It was the other way around last year, we seemed to have a good away form and the home record was a bit indifferent.
"We have to start winning more games away and start picking up more points on the road and not rely on our home form, obviously you want to make your home a fortress and win as many as you can, but it's the away form we really need to build on."