Carolyn Fairbairn, director-general of the CBI, said that every month that goes by without a deal is a wasted month.
"I think 2019 should be the year when a fantastic Yorkshire devolution deal is done," she told the Yorkshire Post.
"There is £1.7bn of Transforming Cities money out there and Yorkshire should be getting some of it.
"Yorkshire should be forging its own skills strategy. It should be driving forward on the connectivity agenda. Every month that is wasted is a month that that isn't happening.
So let's make 2019 the year it happens."
She said that two things need to happen.
"The Government owes it to Yorkshire to be clear about what it didn't like and that should be happening immediately. It should have happened already," she said.
"The Government needs to explain, really clearly, what its criteria are and where they saw the One Yorkshire deal as having shortcomings.
"And then we need to respond. I think we need to listen. What was wrong? How can it be improved? How can business play a role in responding to whatever those concerns are and then get the deal done by the end of the year."
She said the CBI is very supportive of a proper devolution deal for Yorkshire.
"We thought the One Yorkshire deal had many of the attributes of the right kind of solution. It wasn't supported by everybody, but actually here was something that we thought could really fly.
"I think the disappointing thing now is that it has been rejected by Westminster, as yet without any real clarity as to why."
She said the CBI will do everything it can to make sure a devolution deal goes through this year.
"We will be there every step of the way trying to help. Whatever those shortcomings, we will help to address them.
She said that Yorkshire has a thriving economy, a very strong identity and the county should be allowed to fulfil its potential.
"The fact the Sheffield deal happened was fantastic and we are beginning to see the strength of that in the investment it is bringing in.
"The next wave of opportunity is to get the political alignment behind Yorkshire's potential. It's not quite there yet.
She said that politics should not be allowed to interfere with Yorkshire's future success.
"This is just such an opportunity for the region to behave as the major economy that it is. It would be such a lost opportunity if it failed purely because of fragmented politics," she said.
"The next year has to be about bringing that together and making it work. Westminster working locally with local politicians and with local businesses. That's what needs to happen next."
Despite the backing of businesses, trade unions and the Archbishop of York, the future of the proposed One Yorkshire devolution deal is now uncertain.
Last month, Communities Secretary James Brokenshire said Government officials had decided the plan did not fit the criteria for a successful devolution bid.
Council leaders are weighing up their next move and the CBI's support will provide a welcome boost.
At a time when Manchester, Liverpool and the Tees Valley all using devolved powers handed down from Government to tackle issues of regeneration, health and economic growth, Yorkshire has been left on the sidelines.
Local politicians remain resolute in standing by a deal that had the support of all but two council leaders.