Appiah was appointed as the new Black Stars coach this week, replacing Avram Grant, whose contract was not renewed by the Ghana FA.
“I think that this is a new era, and we all have to support him because he is one of our own,” Gyan told Hot FM.
“The Ghana Football Association has made their call, and it’s a man who has managed the team before so we all have to be positive and help him succeed for us.
“I am yet to speak to my colleagues in the national team, but I am sure they have heard and that we will all be looking forward with optimism.”
Appiah will be making a second attempt at the national team job, having coached the Black Stars from 2012 to 2014.
His first game will be against Ethiopia in the Africa Cup of Nations qualifier in Kumasi on June 9.