Clark, who is now committed to the club until the summer of 2016, became a regular in Paul Lambert's first-team squad last season, making 27 Premier League appearances.
The 23-year-old also scored his first goal for the Republic of Ireland, helping them to a 2-0 friendly win over Poland in February.
Clark said: "I've been here since I was 12 years old, progressing from the younger teams through the youth team along with players such as Marc Albrighton, Barry Bannan and another couple who have just signed new deals in Nathan Baker and Andi Weimann.
"It's great that we've all managed to come through together and there's a bond there with this club that's as close as family to us lads especially.
"It's what every young lad dreams about, to be able to play for a club like Aston Villa.
"I've had the honour of captaining the team from youth level right through to the first team and to receive that honour last season was massive for me, a moment I'll never forget.
"This season will be another tough challenge but we have the players and we have a good young squad, everyone is hungry for it, we're working as hard as we can and we can't wait to start."