The Newtownabbey singer was runner up to Pomeroy's Andrea Begley in the 2013 competition, but she was immediately signed to Universal Records and put under the guardianship of Black Eyed Peas star and mentor Will.i.am.
Leah travelled to LA with Will to record the album and is now ready to make her mark in the UK charts as her debut single Home is released on Sunday.
Speaking to Good Morning Britain on Friday, she said: "It's been insane - from two days after the show finished and I signed to Universal, Will flew me out to LA and from the first song that we did together, he picked up the phone was like: "I'm keeping her!"
"And I was his for a year."
Leah was a huge fan favourite when she competed on The Voice, and despite not winning, she said she wouldn't change a thing about her time on the show.
"It's was absolutely amazing, it's was incredible and I've been so blessed and so honoured to get to that stage of the show," she said.
"Andrea (Begley) was a good friend of mine, so we would be behind stage singing: "Who run the world? Northern Ireland...."
From her first audition on the show, Will.i.am championed the singer, and she says she still can't believe she has been allowed to work with him
"I've respected him so much in the industry since I was younger and I've been working with him now for about a year and a half, which means I've been laughing my head off for a year and a half, he is the funniest man.
"But he is also just really kind and so lovely in giving his advice ... and just really encourages me.
"We co-wrote the whole album together and we had the top writers in the industry in the studio with us.
"You can't dream this stuff - this year has been amazing, I went on tour with Will and went on tour with Jessie J.
But despite her rising success and rubbing shoulders with celebrities, including Hollywood stars like Tom Hanks, Leah said she always tries to get home to Northern Ireland when she can.
"I miss (home) a lot, I've lived away from (Northern Ireland) for five years, I moved to pursue music...before the show, but every single time I get two days off I pick up the phone to my managers to say: "I'm going home!"