Chris Read said in a letter to the Government, posted online, that he would support the proposal by his counterparts in Doncaster and Barnsley made in a bid to break the long-running stalemate on the issue.
Earlier this month, Barnsley council leader Sir Steve Houghton and Doncaster Mayor Ros Jones suggested that a mayor for South Yorkshire be appointed, rather than elected at a cost of Â£2m, and for two years rather than four.
This would mean the two authorities would be free in 2020 to join a wider devolution deal with the rest of Yorkshire and the Humber, assuming other civic leaders in the region have reached an agreement.
This solution would mean the Sheffield City Region covering Sheffield, Rotherham, Doncaster and Barnsley would get the extra powers and Â£900m in funding over 30 years promised to them by former Chancellor George Osborne in 2015.
It is a response to a Government proposal that would only allow Doncaster and Barnsley to sign up to a pan-Yorkshire deal in 2022, after an elected mayor has served a four year term.
Council leaders, the majority of whom support a One Yorkshire deal with a single mayor for the region of 5.3m people, will meet today in York in the hope of making further progress.
Barnsley and Doncaster signalled last summer that they wanted to be part of a wider devolution deal, meaning the agreement made in 2015 would no longer come into force and a Sheffield City Region mayor would be elected this May without the promised powers and funding.
The intervention by Chris Read leaves just Sheffield City Council as the only South Yorkshire authority still to agree to the compromise solution.
In his letter to Communities Secretary Sajid Javid, he said: "My priority in all these discussions remains to deliver without further delay the benefits of devolution to the people of Rotherham they have been promised for the last two years.
"The whole of Yorkshire has already fallen too far behind the rest of the country. Rotherham's position remains that we believe the Sheffield City Region Deal is our best opportunity to draw down funding and decision making to strengthen our local economy, and we have not yet seen any counter proposal which we believe would bring the same level of benefit to our borough.
"At the same time, I am acutely conscious that our colleagues in Barnsley and Doncaster have expressed a preference to be part of a wider geographical footprint in the future and it would not be appropriate for anyone to seek to prevent them from doing so."
Coun Read said in his letter to the Minister that he was "pragmatic about how best to make progress, so long as progress is made".
He wrote: "An interim mayoral arrangement, on either an elected or unelected basis, that allowed South Yorkshire to draw down the funding and powers connected to the Sheffield City Region Deal would be welcome.
"I would accept, subject to the usual democratic discussion, the broad outline of the proposal from the Leader of Barnsley MBC and the Mayor of Doncaster in their joint letter to you dated January 9.
"I am relaxed about the possible length of a first mayoral term, but there would seem to be merit to giving consideration to a two-year term, bringing South Yorkshire into the same electoral timetable as other Metro Mayoral areas in 2020.
"At the same time as we accept the right of one or more South Yorkshire councils to pursue and ultimately commit to a deal on a different geographical footprint, it remains equally important that any authorities who would choose to remain within Sheffield City Region in the future should not be disadvantaged, either by a relative reduction in funding per head of population, or a reduction in the devolved powers, or by any moves that would see decisions currently made at a South Yorkshire level removed to a regional level further from the public. We would seek assurances about this as part of our negotiation.
"On this basis we are keen to pursue fruitful discussions at the first opportunity, allowing the Combined Authority to proceed to public consultation ahead of the council moving to consent to the resulting order.
"I have asked the council's Chief Executive to prioritise any conversations with your officials to help facilitate this."
Barnsley MP Dan Jarvis said: “I very much welcome this most reasonable and pragmatic response from the leader of Rotherham council.
“I believe that we are now close to securing an agreement across South Yorkshire that would not act as an impediment to a wider Yorkshire settlement, but as a stepping stone to it.
“We know from the recent decisive community poll results in Barnsley and Doncaster that there is strong support for a wider Yorkshire deal. That support exists right across our county as people increasingly see the value of the influence we would leverage from our combined strength.
“Over the next crucial few days all our elected politicians - both in local government and in Parliament - need to strain every sinew to hammer out the detail of the arrangements for South Yorkshire. We can then get on with developing a wider Yorkshire deal. I am confident that is achievable.”