He wrote the DC comic book story "The Gift". With Leonard Nimoy, de Lancie recorded several audio dramas based on classic science-fiction tales, under the label "Alien Voices". De Lancie has performed as narrator with a number of major orchestras including the New York Philharmonic, the Los Angeles Philharmonic, the Philadelphia Orchestra, the Sydney Symphony Orchestra, the National Symphony Orchestra, the Montreal Symphony Orchestra and Symphony Nova Scotia. He provided the narration for the world premiere of Lorenzo Palomo's "The Sneetches and Other Stories" (based on the book by Dr. Seuss) with the Oberlin Conservatory Orchestra. He has written and directed ten symphonic plays which were produced with the Milwaukee, St. Paul Chamber, Ravinia, Los Angeles, and Pasadena Orchestras. De Lancie was the writer, director and host of "First Nights", an adult concert series at the Walt Disney Concert Hall with the Los Angeles Philharmonic, based loosely on the book of the same name by Thomas Forrest Kelly, which explored the life and music of Stravinsky, Beethoven, Mahler, Schumann, and Prokofiev. In 2006, de Lancie made his opera directorial debut with the Atlanta Opera performing Puccini's "Tosca" from May 18–21. In September 2019, De Lancie narrated as "Forever of the Stars" in the first ever live performances of Ayreon's Sci-Fi concept album Into the Electric Castle. While on stage at the 2012 Ottawa ComicCon, de Lancie announced that he had made plans to co-produce a documentary about "bronies" (older, usually male teenage and adult fans of ""). De Lancie stated he was taken aback by how disrespectfully national news media portrayed the brony fandom. He began a Kickstarter campaign to help fund the documentary, now titled "". The Kickstarter campaign began on May 13, 2012, and by June 10, 2012, had reached a total of $322,022, becoming Kickstarter's second-highest funded film project of all time. Raised by secular parents, de Lancie is an atheist and humanist, who routinely advocates for others who have this view to be open about it. Of his education in a religious school in Philadelphia, he remembers associating religion with manipulation. Rather than developing a religious outlook, de Lancie became fascinated by an ever-changing world: "I’m wondering if one of the things at the core of believing in God, or not, has to do with change.