Kreeft was born 16 March 1937 in Paterson, New Jersey, the son of John and Lucy Kreeft. He took his AB at Calvin College (1959) and an MA at Fordham University (1961). He completed his doctoral studies in 1965, also at Fordham and briefly did post-graduate studies at Yale University.
Kreeft joined the philosophy faculty of the Department of Philosophy of Boston College in 1965. He has debated several academics in issues related to God's existence. Shortly after he began teaching at Boston College he was challenged to a debate on the existence of God between himself and Paul Breines, an atheist and history professor, which was attended by a majority of undergraduate students. Kreeft later used many of the arguments in this debate to create the Handbook of Christian Apologetics with then undergraduate student Ronald K. Tacelli.
In 1971, Kreeft published an article titled "Zen In Heidegger's 'Gelassenheit'" in the peer-reviewed journal International Philosophical Quarterly, of Fordham University. In 1994, he was an endorser of the document "Evangelicals and Catholics Together". He also formulated, with R. Tacelli, "Twenty Arguments for the Existence of God".
Kreeft converted to Catholicism during his college years. A key turning point was when he was asked by a Calvinist professor to investigate the claims of the Catholic Church that it traced itself to the early Church. He said that on his own, he "discovered in the early Church such Catholic elements as the centrality of the Eucharist, the Real Presence, prayers to saints, devotion to Mary, an insistence on visible unity, and apostolic succession."
The "central and deciding" factor for his conversion was "the Church's claim to be the one Church historically founded by Christ." He reportedly applied C. S. Lewis's trilemma (either Jesus is Lunatic, Liar, or Lord): "I thought, just as Jesus made a claim about His identity that forces us into one of only two camps ... so the Catholic Church’s claim to be the one true Church, the Church Christ founded, forces us to say either that this is the most arrogant, blasphemous and wicked claim imaginable, if it is not true, or else that she is just what she claims to be."
According to Kreeft's personal account, his conversion to Catholicism was influenced by, among other things, Gothic architecture and Thomistic philosophy, the writings of St. John of the Cross, the logic of asking saints to pray for us, and a visit to St. Patrick's Cathedral in New York City when he was twelve years old, "feeling like I was in heaven ... and wondering why, if Catholics got everything else wrong, as I had been taught, they got beauty so right..."
Socrates' Children, 4 vols. (2019) — The 100 Greatest Philosophers
Doors in the Walls of the World (2018) - Signs of Transcendence in the Human Story
Forty Reasons I am a Catholic (2018)
Between One Faith and Another (2017) — Engaging Conversations on the World's Great Religions
Catholics and Protestants (2017) — What Can We Learn from Each Other?
How to Be Holy (2016) — First Steps in Becoming a Saint
I Burned for Your Peace: Augustine Unpacked (2016) — Burned for Your Peace: Augustine Unpacked
The Philosopher's Bench (2015)(DVD) — Catholic philosophers Peter Kreeft and Thomas Howard bring philosophy to the 'man in the street'
Letters to an Atheist (2014) — Wrestling with Faith
Practical Theology (2014) — Spiritual Direction from Aquinas
Socrates Meets Kierkegaard (2014) — Questions the founder of Christian existentialism
Charisms: Visions, Tongues, Healing, etc. (feat. Dave Nevins) (2013) — catalysts to "two-way" interactive prayer
Jacob's Ladder (2013) — Ten Steps to Truth
Summa Philosophica (2012) — 110 Key Questions in Philosophy
An Ocean Full of Angels (2011)
Socrates Meets Hume (2010) - The Father of Philosophy Meets the Father of Modern Skepticism
Between Allah & Jesus: what Christians Can Learn from Muslims (2010)
If Einstein Had Been a Surfer (2009) — A Philosophy of Surfing
Socrates Meets Kant (2009) — The Father of Philosophy Meets His Most Influential Modern Child
Because God Is Real : Sixteen Questions, One Answer (2008)
I Surf Therefore I Am (2008) — An exploration of Surfing
Before I Go (2007) — Letters to Children About What Really Matters
Pocket Guide to the Meaning of Life (2007)
The Philosophy of Jesus (2007) — On the wisdom of Jesus
Socrates Meets Descartes (2007) - The Father of Philosophy Analyzes the Father of Modern Philosophy's Discourse on Method
The Sea Within (2006)
The Philosophy of Tolkien: The Worldview Behind "The Lord of the Rings" (2005)
Socrates Meets Sartre : Father Of Philosophy Meets The Founder of Existentialism (2005) — Socrates and Jean-Paul Sartre
You Can Understand the Bible (2005) - a combination of his previous books You Can Understand the Old Testament: A Book-by-Book Guide for Catholics (1990) and Reading and Praying the New Testament: A Book-by-Book Guide for Catholics (1992)
Socratic Logic (2005) — A textbook on classical logic.
The God Who Loves You (2004)
Socrates Meets Marx (2003) — Socratic dialogue between Socrates and Karl Marx
Socrates Meets Machiavelli (2003) — Socratic dialogue between Socrates and Machiavelli
Philosophy 101 by Socrates (2002) — An introduction to philosophy via Plato's Apology
Three Approaches to Abortion (2002)
Celebrating Middle Earth: Lord of the Rings (2002) — On western civilization
How to Win the Culture War: A Christian Battle Plan for a Society in Crisis (2002)
Socrates Meets Jesus (1987/2002)— Socratic dialogue with students of Harvard University's Divinity School
Catholic Christianity (2001)
Prayer for Beginners (2000)
Refutation of Moral Relativism — Dialogues between a relativist and absolutist (1999)
The Snakebite Letters Devious Secrets for Subverting Society (1998)
The Journey A Spiritual Roadmap For Modern Pilgrims (1996)
Ecumenical Jihad: Ecumenism and the Culture Wars (1996)
Angels (and Demons): What Do We Really Know About Them? (1995)
Talking to Your Children About Being Catholic (1995) — A treasure trove of ideas
Handbook of Christian Apologetics (Pocket Version) (1994)
Shadow-Lands of C.S. Lewis : The Man Behind the Movie (1994)
C. S. Lewis for the Third Millennium (1994) — Six essays on Lewis' Abolition of Man
Handbook of Christian Apologetics (with Ronald K. Tacelli) (1994)
Your Questions, God's Answers (1994) — Solid responses for Catholic teens
Christianity for Modern Pagans: Pascal's Pensees (1993)
Shorter Summa (1993) — Shorter version of Kreeft's Summa of the Summa
Back to Virtue (1992) — Reprint of For Heaven's Sake: The Rewards of the Virtuous Life (1986)
Prayer: The Great Conversation (1991) — Straight answers to tough questions
Three Philosophies of Life (1990) - Ecclesiastes (life as vanity), Job (life as suffering), Song of Songs (life as love)
Summa of the Summa (1990) — Summa Theologica edited and explained for beginners
Making Choices: Practical Wisdom for Everyday Moral Decisions (1990)
Everything You Ever Wanted To Know About Heaven... But Never Dreamed of Asking (1990)
Heaven, the Heart's Deepest Longing (1989)
Fundamentals of the Faith, Essays in Christian Apologetics (1988)
Making Sense Out of Suffering (1986)
Yes or No? (1984) — Straight Answers to Tough Questions about Christianity
The Best Things in Life: (1984) — Twelve Socratic dialogues on modern life
The Unaborted Socrates (1983) — Socratic dialogue on abortion