The talented 19-year-old has penned a two-year deal with the club after impressing Hull coach Richard Agar in a match for Cumbria under-19s.
“We had a look at James recently and have decided to offer him a part-time deal and he’ll join our under-20s squad,” said Agar.
“He has impressed at academy level and is a representative player that has attracted a bit of interest from a number of clubs.”
A loose forward or hooker, Newton was spotted by former Barrow and Whitehaven coach Paul Crarey, who is now a talent scout for the Black and Whites.
Newton is due to link up with Hull before the end of the month and is looking forward to the challenge ahead.
“It’s going to be great being alongside all those top players and internationals,” he said.
“I’ll go straight into the under-20s squad and Richard has said to me as soon as I get in there and prove that I am good enough, then I will step up to first-grade football.”
The youngster will join fellow Cumbrian Ewan Dowes at the KC Stadium.