Mr Devonport was 35 when he was caught selling heroin in 2007 and a self-proclaimed "career criminal" who had already served three jail sentences.
Facing the prospect of another lengthy prison term, he took the advice of another inmate who told him - "don't serve time, let time serve you".
"I tried using the time constructively," Mr Devonport, who served as a Chieftain gunner in the First Royal Tank Regiment, said.
"I really wanted to sort my life out by then."
He enrolled at the Open University and obtained a first-class honours degree in sociology, but it was when he stumbled across a painting class organised by charity Care After Combat, that he changed his life's trajectory.
"I was never really an arty person," he said.
"I’d look and admire but I never thought I could do it myself."
However, Mr Devonport, who grew up on a council estate in Leeds and left school with no qualifications at 15, said he took to the class "like a fish to water".
His first painting - "a little landscape" - may not have been his best work but he said it was the process of creating it that really struck a chord.
Having never imagined he would be an artist, he won his first national award while still in prison.
"It’s not been a conscious decision, it’s like life has directed me that way," he said.
Despite his successes, navigating life after his release in 2014, his reintegration into society and the stigma of incarceration, were challenging.
His last run-in with the law was in 2018, when he was jailed for producing cannabis.
Mr Devonport, who is now a father to Sinead, eight, said it was his art that anchored him and inspired his first exhibition titled "Unlabelled".
"Coming into a world where you are not as accepted, you are a bit like driftwood," he said.
"Being an artist gives me a sense of who I am, a sense of identity. I was lost. It’s given me something to attach to."
Identity, his experience of the justice system as well as his time in the Army on active duty in Germany and Northern Ireland, are often themes that feature in his paintings.
