"founding mission" is correct and usable in written English.
You can use it to refer to the overarching purpose that was the impetus for the establishment of an organization, a company, or a movement. For example, "The founding mission of the company was to create a sustainable source of renewable energy."
These flaws and foul-ups cause untold anguish and dishonour the founding mission of our healthcare provision.
Part of our founding mission was to develop a community forum for issues around civic education and engagement and history.
They build on the BBC's many strengths but remain true to our founding mission – to inform, to educate and to entertain.
This may involve reemphasizing a firm's founding mission, as Danone's CEO did in 2000 to refocus the company on its origins as a manufacturer of healthy food.
Dr. Blumberg's vitality, inquisitiveness, distinction as a scientist, and dedication to our founding mission of "promoting useful knowledge" enhanced his years of leadership and service on the Society's behalf.
The Brexit vote for the UK to leave the EU has caused a political crisis, which raises fundamental questions about the founding mission of the EU as a largescale nation-building experiment aiming at promoting democracy, peace and prosperity across Europe through an "ever closer union among the peoples of Europe".
He went to lengths to praise them for building Victory Gardens, but he also said that its founding mission — to produce new plays by a diverse mix of writers — invited the changes that he is undertaking in this, his first time running a theater.
What began as a multi-sectoral focus in our founding mission of educating leaders for business and society has become a multidisciplinary focus in our integrated M.B.A. curriculum, which we launched in 2006.
Delrina was Bennie's second major entrepreneurial start up after co-founding Mission Electronics, a home theatre equipment company.
Its founding mission to ensure "the highest possible level of health" for everyone is vague, and unattainable given its resources.
Its founding mission to make the world's information accessible comes into conflict with China's habit of repressing speech.
