Exactly one year on from being named as skipper for the first time, Grealish will lead out a team he has supported since he was a boy in Villa's first major domestic final for a decade on Sunday when they take on Manchester City at Wembley in the Carabao Cup.
Following an outstanding season, despite Villa's battle against relegation, Grealish will also have an opportunity to again impress England manager Gareth Southgate, and on the biggest stage.
With friendlies at the end of March against Italy and Denmark as part of England's preparations for this summer's European Championship, Smith feels Grealish is deserving of his chance after watching him mature over the past 12 months since being handed the captain's armband.
Asked whether he had noticed much change in Grealish, as a player and a person since being named as skipper, Smith said: "As a player yes, as a person, no.
"I can only be honest, and from the moment I came in – and you hear the stories about a person, about a player – what I've experienced is a player who wants to accept responsibility as a group leader.
"Obviously, staying in this league is one of the biggest things to help us keep Jack Grealish. He wants to play at the highest level and he wants to win trophies.
"We're going to work hard. We have to work hard on Sunday to win that trophy.
"Jack's future, like the rest of the players, is down to what happens over the next three months. What we can do is assess it then."