Amina Shah previously served as Director of Programme at the Scottish Book Trust, as well as the University of St Andrews Libraries and Museums.
Ms Shah, who also worked with the National Library of Scotland (NLS) as a member of the Board of Trustees, has more than 25 years’ experience in the sector.
NLS said her appointment brings a wealth of leadership experience from both public and academic libraries.
Ms Shah said it was “a great honour and privilege” to lead the Library in the next chapter of its history.
“I am excited to get to work with the team, the Board and the people of Scotland to shape and share our incredible collections and to use them to support our recovery from the educational, cultural and economic inequalities brought about by the pandemic.”
She added: “Scotland has always been a nation of bards and blethers, and I believe there is no better way for us to understand ourselves, each other and the world around us, than to capture the stories of today, treasure them for the future and share them widely within our communities and across the world.”
As former CEO of the Scottish Library and Information Council, Ms Shah also led the development of Scotland's first National Strategy for Public Libraries.
Commenting on her appointment, Chair of the National Library, Simon Learoyd said: “I am delighted that our new Chief Executive will be Amina Shah.
“In a large and very strong field of candidates, Amina impressed us all with her obvious passion for the Library and everything it represents and aspires to be.
“Amina is massively ambitious for the Library and its place in wider Scottish society. She brings a huge amount of experience of Scottish culture and leadership in the library sector in particular.
“I have every confidence that she will be a great Chief Executive of the Library taking us into our centenary year in 2025.”
Ms Shaw will take up her new post on October 4 after the current National Librarian, Dr John Scally, retires.