The midfielder has signed a three-year deal having watched Villa's 1-1 Sky Bet Championship draw with Huddersfield on Tuesday.
Jedinak lost the captaincy at Palace, having skippered the side for the last four seasons, with Scott Dann handed the armband by boss Alan Pardew.
He becomes Villa's sixth signing of the summer but will not be available until his EFL and Football Association registration is complete, which is subject to the issuance of the relevant UK Visa and Immigration documents.
Villa travel to Derby on Saturday with the side having won, drawn and lost one of their opening three league games since relegation from the Premier League last season.