This time last year Watford striker Deeney thought his life could get no worse. His dad died of cancer aged 47 and, soon after, his great grandma passed away.
Deeney's son's third birthday would, under normal circumstances, have lifted the 24-year-old's morale, but all his enjoyment had been sapped by something which he calls "the incident".
Using such a term may seem to imply that the incident in question was not serious, but it was.
What Deeney refers to is his conviction in June 2012 for affray following a brutal attack in Birmingham. The former bricklayer was jailed for 10 months after he became involved in a fight with four students.
Instead of being part of the bright new era at Watford under Gianfranco Zola, Deeney left his team-mates, girlfriend and son for Winson Green prison in Birmingham.
Given that Fred West was one of the former inmates at the Category B jail, Deeney was dreading his first day.
"As I walked through, one of the guards told me: 'Just so you know, they all know who you are, they've all read the papers.'
"I just said: 'Cheers'."
Deeney took his place in a shared cell measuring 6ft x 8ft. He barely communicated with his cellmate.
"I don't know his name, I never asked. He was just another criminal," Deeney said.
"On my first night I just laid there in bed thinking: 'Oh s***, this is cold.'
"I had one blanket. It wasn't even a blanket. It was a sheet, and the bed was caved in."
Deeney moped around for two days and he then started writing incessantly - to family, to friends, even to himself.
He filled a full ringbinder which he keeps at home.
"When I feel a bit s*** now I can just have a look through them and think: 'It's not too bad.'
Deeney's morale improved after a while. None of his inmates "roughed him up", he says, and he was moved to Thorn Cross prison in Warrington - a category D jail.
There he was kicked out of his cell at 7am and, apart from meal breaks, he spent the rest of the day cleaning the yard.
It was a tiresome job, but if he did not do it he would have been locked up for 23 hours a day watching day-time TV programmes. "And that's not very good for anyone," he points out.
Watford did not allow Deeney to play in the prison's football team, so his only chance to take in the game was via television.
The more relaxed regime at Thorn Cross meant Deeney was allowed Freeview, giving him access to Match of the Day and the Football League Show.
One of the first games he watched was Watford's dramatic 3-2 win at tomorrow's opponents Crystal Palace, which came after Matej Vydra's injury-time winner.
"We got locked up at 7.30pm so it was hard to stay awake for four or five hours, but I watched the highlights. It was a great goal by Vyds at the end," he said.
"Watching football was a treat. Anything was a treat.
"It made the days pass quicker and kept me focused on what needed to be done, because I could see the lads playing and I needed to keep myself in shape."
Deeney was released after three months, but his joy was tempered by doubts over his future.
He had good reason to be worried. Deeney was nearly broke, he had not played football in three months and Watford had a new manager and owner.
He was therefore delighted when Zola gave him a second chance.
"I was panicking. I was quite nervous," Deeney said.
"Sometimes you get a stigma attached to you. I was worried (Zola) might not like me.
"But we had one conversation and he said I reminded him of Carlton Cole, which was nice.
"Once he saw me get back working and doing the fitness tests he knew I was going to be part of his plans. I was quite lucky."
Deeney has repaid Zola handsomely for the faith he showed in him.
He has scored 20 goals - the most crucial of all coming two weeks ago to send Watford through to the play-off final against Palace.
Off the pitch Deeney insists he is fully rehabilitated. He has stopped drinking to excess and he has not forgotten about the family he let down.
He has acquired 96 tickets for them for today's final and he regularly visits his dad's grave to read him some of the letters he wrote in prison.
He describes his stint behind bars as "the best thing that has ever happened to me," and he has a new perspective on life and football matches - even if they have £120million riding on them.
"I don't feel any nerves now. It's football. There is much more to life," he says.