The midfielder has been a regular for David Unsworth’s Under-21s side this season and made his first-team debut against FC Krasnodar in December.
The midfielder told evertontv he was delighted to put pen to paper.
He said: “It’s what I have wanted to do ever since I joined the Club, so it’s great to be able to finally say I’m a professional footballer for Everton.
“I’ve been here since I was seven. I was with a few different clubs before that, but then I got the opportunity to join Everton and I’ve enjoyed everything about it all the way through the age groups.
“All the coaches have been brilliant with me, I’ve been on some great trips with the Club and there are always opportunities.”
The Ormskirk-born left-footer also reflected on the night of his first appearance for the senior side back in December.
Dowell says he is now relishing the prospect of learning from some of the Club’s key first-team players.
“To be honest, [this season] has probably exceeded my expectations in terms of what I wanted to achieve,” he declared. “I made my first-team debut which has been the main highlight of my year – but we’ve also had a good run in the Under-21s and Under-18s leagues as well.
“It was unbelievable and being an Evertonian myself, it was a dream come true. All my family are Blues as well so they were there watching and they were made up for me.
“Ever since I came up to the seniors this year, it’s been something that I have noticed – the first-team players are really friendly and really helpful.
“They’ll always look to give you little tips for your game which is obviously really good.
“Roberto has been great, too. He has congratulated me [on signing a professional contract] and he’s told to just keep going and to work even harder.”