Begg was born in Glasgow, Scotland in 1952, and still carries a distinctive accent after nearly 30 years of ministry in the United States. On November 2, 1972, his mother died. Regarding the incident, Begg wrote that "more spiritual progress is made through failure and tears than success and laughter." Begg graduated from The London School of Theology in 1975 and then served eight years in Scotland at Charlotte Baptist Chapel in Edinburgh and Hamilton Baptist Church in Lanarkshire. Dr. Begg is a Council member of the Alliance of Confessing Evangelicals. He was educated at Trent University and Westminster Seminary. Among Begg's influences are: Martyn Lloyd-Jones, John Stott, Derek Prime, Eric Alexander, Sinclair Ferguson, Dick Lucas, Eric Liddell, Charles Haddon Spurgeon, Jim Elliot, and Hudson Taylor.

His wife, Susan, is American by birth, and Begg himself became a U.S. citizen in 2004. He and his wife have been married over 30 years and have three grown children. In 2004, he played Stewart Maiden in the film Stroke of Genius.

Begg believes in the inerrancy and supremacy of Scripture, and in the saving power of Christ alone. He has stated that the core belief of Parkside Church is "that Jesus Christ, the Son of God, has died as an atoning sacrifice for our sins, and that to know Him is to know life, both now and forever [...] Jesus Christ is the only Savior, because Jesus is the only one who is qualified to save." Fellow theologian and author R.C. Sproul wrote that "Alistair Begg incarnates this Neo-Puritan movement, a humble champion who has been galvanized by a magnificent obsession with the God-centered life. [...] Begg is an anachronism. He breaks the mold of contemporary evangelicalism, the mold that has been marred by narcissism and sullied by a preoccupation with a man-centered focus on method, technique, and a virulent form of self-esteem." His work has been praised by such people as John MacArthur, Max Lucado and Joseph M. Stowell. Begg is critical of Hyper-Calvinism and he also removed himself as one of the speakers at the "REiMAGINE" conference because of some of its other speakers, such as Leonard Sweet who has been criticized for New Age teachings.