Martin's career as an apologist began at the age of fifteen after being baptized in Hegemen Chapel at The Stony Brook School (Stony Brook, NY). While in college and graduate school, he often skipped eating during his lunch hours to answer a variety of tough questions about the Bible and the Christian faith while standing on the corner of Wall Street and Broadway, in New York City. Martin has indicated in various book dedications and in audio recorded lectures how he was mentored by Frank Gaebelein (Headmaster, The Stony Brook School), Wilbur Smith (1894–1976) (author of the apologetic text "Therefore Stand"), and the Presbyterian Bible teacher Donald Grey Barnhouse (1895–1960).