Appiah, who spent 10 seasons in the Italian league, insists that the Ghana international will continue to succeed with his new club after making the switch from division rivals Udinese this summer.
"Playing for a top team, all you need to do is to build your confidence," he told Goal.com.
"I think that Kwadwo Asamoah has proved that he is one of the best midfielders in Serie A. I believe he is going to do well there. Juventus is a great club and I wish him all the best."
Appiah spent two seasons at Juventus from 2003-05.