Norfolk’s 17-year-old Hewett and world number three Reid took nearly three hours to battle past tournament top seeds Joachim Gerard and Stephane Houdet 5-7 6-2 7-6(4).
The British pairing take on second seed French duo Michael Jeremiasz and Nicolas Peifer at the Nottingham Tennis Centre on Saturday.
For Hewett, making it to the biggest final of his young career comes as a huge thrill after going out of Wimbledon in a gruelling semi-final loss to Reid and Jeremiasz.
“After the disappointment of last week at Wimbledon to win that tie-break in the end was good for me,” said world number one junior Hewett, who went out in the first round of the men’s singles at the British Open on Tuesday.
“We both went for it, me especially, I really needed to go for it. It was another three-hour match and I’m glad to have come out on top this time.”
Already Hewett and Reid have enjoyed success on court together this year, picking up two doubles crowns in Australia.
However, making to the decider in Britain’s biggest event outside of Wimbledon is a major career milestone for the right-hander ahead of the 2016 Paralympic Games in Rio.
“It means a lot to me, I’ve been training really hard in doubles recently with Rio coming up,” said Hewett.
“For me to get to the final with Gordon really puts into perspective what we can do as a pair.
“For us to come through that and keep our focus in the end was really great.”