Former Treasury Secretary of the United States Lawrence H. Summers has been named chair-elect of Boston-based Citizen Schools’ national board of directors.

Citizen Schools is a national nonprofit that partners with middle schools to expand the learning day for children in low-income communities.

"Citizen Schools is developing a new model for a longer, more engaging and more effective school day," Eric Schwarz, co-founder and CEO of Citizen Schools, said in a statement. "I am excited Larry Summers has agreed to chair our board of directors. He brings a deep understanding of education and its connection to economic growth and fairness. With his leadership, Citizen Schools is positioned to build on its track record of innovation and growth."

Summers will join the board of directors immediately and become the chair in early 2014. He will succeed Andrew Balson, who will remain on the board.

In the last two decades, Summers was the director of the National Economic Council for President Barack Obama and served as the 71st secretary of the treasury for former President Bill Clinton. He is the Charles W. Eliot university professor and president emeritus at Harvard University and serves on the executive committee of the Teach For America national board.