Doe, who boxes out of CNC Christchurch, defeated Savannah Williams of Acock's Green on Sunday, November 23.
Against an opponent who is a multiple national champion and someone who has represented England in the open class under 54kg weight category, Doe made a strong start.
She stuck to her gameplan, aiming to contole the contest with her range and movement on her feet.
Doe was on top after the second round as she stood and traded blows a few times with Williams, before a fantastic third round performance saw her force her opponent to miss in the exchanges.
That saw her clinch a unanimous points decision in the finals at Bridlington.
Joe Hayes of Doe's club in Christchurch praised the boxer.
"Ella is one of the most dedicated boxers, she never moans, is always smiling and always takes on board what the coaches say," he said.
"Even if she is injured she is in the gym working on her weaknesses and there is no one who deserved to be crowned national champion more than her.
"Her dad, Nick Doe, one of our coaches, gives up a lot of time and puts all the effort into Ella and takes her round the country sparring.
"He also puts as much time into the other boxers in CNC Christchurch which is great to have in the gym."
Hayes celebrated what has been a successful year for the club, with multiple box cup winners.
Alfie Woods was crowned King of the Ring in Sweden, Kieran Allum won the Western Counties Elite belt and Sam Carr has been in two national finals, losing on 3:2 split decisions, in contests Hayes said most thought he had won.