Jon Sweeney can’t sit still. When not keeping his three-year-old daughter from climbing on bookcases, he's writing a column on hell for the Huffington Post; gathering research or writing a new book; speaking at churches, temples, and colleges on a range of topics, from popes to popular history; or steering a book through the publishing process in his role as publisher at Paraclete Press.

Motivated by a love for organized religion and an insatiable desire to always be learning, Sweeney's religious evolution has been as peripatetic as his writing and publishing careers. He grew up in an evangelical home in Wheaton, Ill., and attended Wheaton College. “I was convinced in my teens that I was going to be an evangelical pastor," says Sweeney. "But then I took a progressive turn, and I realized I wasn't called to preach." During his years working as manager of Divinitas Books in Cambridge, Mass., he left evangelicalism behind and became a committed Episcopalian for 21 years. In 2009, Sweeney formally converted to Catholicism on the Feast Day of St. Francis. But today, in a more unexpected twist, his primary congregational involvement is Jewish, and he prays with his wife, a rabbi at the Ann Arbor Reconstructionist Congregation. "I'm actually a Catholic," Sweeney says, "but that doesn't really define me. In many ways I'll religiously and spiritually be 'almost'."

Sweeney comes to publishing naturally. His father, Mark, was the publisher at Moody Press in the 1980s. While at North Park Theological Seminary in Chicago, Jon Sweeney landed a job as buying manager for the Covenant Bookstore, just across the street. After graduating with a Master’s in Divinity, Sweeney moved to Atlanta, where he became the Southeast sales rep for Augsburg Fortress, the publishing arm of the Evangelical Lutheran denomination.

After 2 ½ years, “because I was very interested in trade publishing,” Sweeney headed for Jewish Lights Publishing in Vermont, where he became v-p of sales and marketing. In 1999 he co-founded their SkyLight Paths imprint, which publishes multi-faith spirituality books. He was associate publisher and editor-in-chief there for five years before heading to Paraclete Press on Cape Cod.

In 2000, Sweeney “just got inspired” to write his first book, Praying with Our Hands: 21 Practices of Embodied Prayer from the World’s Spiritual Traditions (SkyLight Paths), featuring black-and-white photographs of praying hands from various religious traditions. Sweeney then turned to one of his greatest influences, St. Francis of Assisi, and edited an abridged edition of Paul Sabatier’s biography of the saint, The Road to Assisi: The Essential Biography of St. Francis (Paraclete Press, 2004).

Since then Sweeney has edited or written another 20 books. He co-wrote with his wife, Rabbi Michal Woll, Mixed-Up Love: Relationships, Family, and Religious Identity in the 21st Century (Jericho Books, 2013), about, among other things, making an interfaith marriage work. And in Inventing Hell: Dante, the Bible, and Eternal Torment (Jericho, June), Sweeney traverses each canto of Dante’s Inferno to demonstrate that “the Christian theology of Hell owes more to medieval philosophy and theology than the Bible.”

How does he manage to write so much so quickly? “I have three children, so I haven’t slept well in 21 years. I get up at 4 or 5 a.m. and have a few good hours to write.” Sweeney acknowledges that “for better or worse, writing a book is almost like a rummage sale; I begin with gathering all the stuff together that’s been hanging around in my life and library and start reading and researching. After about a year, I’m ready to start writing on the topic.”

Sweeney must have enough for quite a few yard sales: In addition to his Dante book, he’ll be publishing When Saint Francis Saved the Church: How a Converted Medieval Troubadour Created a Spiritual Vision for the Ages (Ave Maria) in September, and he’s working on a volume on Emerson for the Modern Spiritual Masters series (Orbis), as well as a biography of St. Francis that tells the saint’s story through the conflicts that shaped his life. While Sweeney is writing about one of the most famous religious figures of the Middle Ages, he seems to be a Renaissance man himself.