They will attempt to avenge their 2-1 defeat by the Swiss in 2018 and secure a first trophy in the mixed team competition for Germany since 1995.
Wimbledon champion Kerber saved four break points in the second set to beat an error-prone Ashleigh Barty 6-4 6-4 to set the ball rolling for Germany on Friday, before Zverev swatted aside Matthew Ebden 6-4 6-3 to seal the win.
Germany finished top of Group A after winning all three of their matches, while the Swiss topped Group B with two victories from their three encounters.
"It's nice to be back in a final. It's nice to play Switzerland as well," ATP Finals champion Zverev said.
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"We lost a very close match last year, and we definitely wanted to get there and compete for the title again. And that's why me and Angie decided after last year's final that we're definitely going to come back here to Perth."
Australia claimed the dead mixed doubles rubber 4-0 4-3(1) to sign off with a consolation win.
Earlier, Spain defeated France 2-1 in their final round-robin encounter as former world number one Garbine Muguruza beat Alize Cornet 6-1 6-3 before veteran David Ferrer battled past Lucas Pouille 6-4 6-7(5) 7-6(2).
"It's going to be the last matches in my career and I try to enjoy every point that I play," Ferrer, who is set to retire this year, said.
"For me it's a pleasure to play here in this centre court at Hopman Cup. I never played (before) but I am happy to have the chance to play one time here."
Muguruza withdrew from the mixed doubles rubber with a left thigh injury that troubled her during the singles clash and was replaced by American teenager Whitney Osuigwe, ranked 201 in the world, as Spain went down 4-2 4-2.
(Reporting by Shrivathsa Sridhar in Bengaluru; Editing by Toby Davis)
