The 1967 edition added more general and expanded articles on science, education, and the liberal arts plus ecumenism, reflecting the Second Vatican Council of 1962-65.

In 2001, in collaboration with the Catholic University of America, Gale Publishing, a subsidiary of the Thomson Corporation, published a Jubilee Volume: The Wojtyła Years, which focuses on the pontificate of Pope John Paul II and included thematic essays that covered the person, his work, and pontificate in two parts: The second part offers various sections (e.g. "Magisterial Documents", "People and Places, Institutions and Events"), the content for each of which is arranged with entries in alphabetical order.

In addition to the hundreds of new signed articles on a wide variety of topics, the 2002 edition also featured biographies of contemporary religious figures; thousands of photographs, maps and illustrations; and some updated bibliographical citations.

"[2] Controversial subjects were, to some extent, avoided in the second edition; for example, as Jan Malcheski and Herman Sutter both noted in their reviews, an article from the 1996 NCE1 supplement on pedophilia was omitted in the NCE2.

[6] In the summer of 2006, the publisher Gale and the Catholic University of America Press developed a plan for ongoing updating of the second edition in print and electronic (eBook) formats.

[25] Supplement 2010, published in June 2010, focused on the theme "Church in Modern History", with particular emphasis on World War II and thereafter.

Supplement 2011 focused on the theme "Church and the Arts and Music"; among its new articles were one on the sex abuse crisis and one on Pope Benedict XVI, as well as new entries on St. Mary Helen McKillop (1842–1907) and St. Andre Bessette (1845–1937).