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 number two 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 number seven Pegula took control of a see-sawing clash by grabbing a crucial break in the fifth game of the decider and held firm from there to send her country through with a booming forehand shot that Boulter returned into the net on matchpoint.
Emma Navarro earlier put the USA ahead 1-0 when the world number 18 fought 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.
"I had a ton of support from the ladies in my team. I feel a ton of pride playing for my country, it means the world to me to have the American flag on my chest," Navarro said.
"I was hearing you guys cheering me on. Britain (fans) were pretty loud in this match, so I needed all the help I could get."
The USA 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.