The body's new chief executive said it would support "the brightest minds, while recognising that the brightest minds come in many diverse forms".
Sir Mark Walport and Mr Johnson were speaking at a launch event for UK Research and Innovation (UKRI) in London.
Commenting on the issue of diversity in science, Prof Ottoline Leyser of the University of Cambridge said diversity was essential for a creative and innovative research system.
"This requires an inclusive research culture, which in turn depends on diverse assessment criteria for researchers, diverse funding types and diverse routes for researchers into and out of the research base," she said.
"The creation of UKRI is an opportunity to embed diversity in all aspects of the research system."
UKRI will incorporate the seven existing research councils, as well as Innovate UK and Research England (the research arm of the Higher Education Funding Council for England).
"Research is a global activity," said Sir Mark.
"We practise in an international landscape, we are internationally diverse, and much of the science that's done today is international in nature, both through the instruments that are needed, which can't be funded by any one nation alone, and also by the desire of researchers to work with the best counterparts, wherever they are."
He said the world of science and research is changing, driven by big data, interdisciplinary research and global collaborations. The world of business and industry is also in flux, driven by factors such as data and the need to re-use resources.
Faced with all of those changes, it made sense "to look at our research and innovation landscape in a much more integrated fashion," said Sir Mark.
He said UKRI's vision was "to be the best research and innovation agency in the world" through:
- Pushing the frontiers of human knowledge
- Delivering economic impact and creating better jobs
- Creating social impact by supporting society to become stronger and healthier.
At the event, Mr Johnson also confirmed an investment of £100 million to attract global talent to the UK through its new Ernest Rutherford Fund.
The fund will provide fellowships for early-career and senior researchers, from the developed world and countries such as India, China, Brazil and Mexico.
"Rutherford and his immense contributions to science exemplify our vision of a Britain that is open to the best minds and ideas in the world, and stands at the forefront of global collective endeavours to understand, and to improve, the world in which we live," said Mr Johnson.
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