Clark made his first-team debut for Villa in an EFL Cup tie against Wigan Athletic last season, but the 19-year-old spent the rest of the campaign in the reserves.
However, the Welshman has now been provided with a year of senior football with Port Vale, and manager Neil Aspin is delighted to add extra depth to his squad.
Aspin told the club's official website: "We needed to get cover for full back. It is an area where we don't have a lot of cover. We were trying to bring somebody in who had experience of playing in both full-back positions, which he has.
"Experience wise, he is inexperienced but he has played for the under-23s and he has played in the first team in the cup last season. He needs to get away from that level of football and start playing at this level. So, we are pleased to bring him in and he will give us some competition in those areas."
Vale - who currently sit in 10th place in League Two - have now made 13 signings this summer.