Federer, who has won a record 17 Grand Slam titles, needed almost an hour and a half to eliminate Zverev 6-1, 7-5, 6-2 in style, reports Efe.
Federer is now the oldest tennis player, at 35 years and 174 days, to reach the Australian Open semi-finals, surpassing American Arthur Ashe.
The Swiss maestro is the former world No.1 and currently ranked 17th due to a knee injury that forced him off the courts last year, only to return to try to claim his fifth Australian Open title.
He is also has a record 41 Grand Slam semi-finals throughout his career.
The Swiss veteran will play the next round against his countryman, Stanislas Wawrinka, champion of the 2014 edition, who defeated French Jo-Wilfried Tsonga 7-6 (7-2), 6-4, 6-3.
Head-to-head, Federer has won 18 matches out of 21 with Wawrinka, including the last two encounters in the US Open and the 2015 ATP World Tour Finals in London.
"If someone would have told me I'd play in the semis against Stan, never would I have called that one for me," said Federer told the Australian Open's official website.
"For Stan, yes, but not for me. I honestly didn't even know a few days ago that he was in my section of the draw or I'm in his section."
Despite emphasising his self-confidence and desire to win, Wawrinka praised Federer for his inspirational return, and acknowledged him as the best player of all time; however, he pointed out that he has already defeated his compatriot in a Grand Slam tournament.