Giglio was born in Atlanta on June 30, 1958. He grew up in the Atlanta suburb of Smyrna and graduated from Campbell High School. He later graduated from Georgia State University and earned a Master of Theology from Southwestern Baptist Theological Seminary in Fort Worth, Texas. Later he went to Grace Theological Seminary to pursue a Doctor of Ministry degree. After finishing seminary, Giglio and his wife Shelley, whom he married in 1986, began a weekly Bible study called Choice at Baylor University where he was doing graduate studies. After several years, over 10% of the Baylor student body was attending the weekly gathering, and Giglio's heart for the significance of the "university moment" was set.