The first meeting between the two countries in the elite women's team competition for more than 33 years was settled by Jessica Pegula, who handed the Americans an unassailable lead after beating British No.2 Katie Boulter 3-6 6-4 6-2.
"It's the first time I'll be in a final," said Pegula.
"I think everybody in the team, it'll be our first time, so it'll be a new experience for us, but there's nobody else that I would rather share it with.
"We have an awesome team and awesome coaches. We're excited to be back and hopefully we'll take the title."
World No.7 Pegula took control of a see-sawing clash by grabbing a crucial break in the fifth game of the decider and held firm to send the US through with a booming forehand that Boulter returned into the net on match-point.
Emma Navarro earlier put the US ahead 1-0, fighting back from a set down in another contest full of momentum shifts to beat Sonay Kartal 3-6 6-4 6-3 in front of a loud crowd at the Shenzhen Bay Sports Centre Arena.
"It means the world to me to have the American flag on my chest," Navarro said.
The US will now look to claim their first title since 2017 in the event formerly known as the Fed Cup, but they will face a tough test on Sunday against Italy, who will aim to successfully defend their crown after reaching their third successive final.
