Smith was born on 14 February 1957, to Frank Eric Smith and Rosemary Clayton Smith. His family is originally from Trowbridge and Westbury, Wiltshire. He was educated at Trowbridge Grammar School for Boys.
Smith studied theology at the University of Birmingham, and graduated with a Bachelor of Arts (BA) degree and a Master of Arts (MA) degree. His master's thesis was titled 'The Poetic Art of the Hebrew Prophets'. He undertook postgraduate research at the University of Wales, Bangor, and graduated with a Doctor of Philosophy (PhD) degree. He trained for the priesthood at Wycliffe Hall, Oxford.
After ordination as a deacon at Petertide 1981 (on 28 June in Bradford Cathedral) and as a priest the Petertide following (27 June 1982 at Christ Church, Skipton) — both times by Geoffrey Paul, Bishop of Bradford, he began his career as assistant curate at St Lawrence and St Paul Pudsey. In 1982 he was ordained a priest at Christ Church, Skipton. In 1984 he took up the post as chaplain of the Lee Abbey Community near Lynton in North Devon where had particular responsibility for mission and the creative arts. In 1989 he was appointed as the Diocesan Missioner and Executive Secretary of the Board for Mission and Unity for the Diocese of Lichfield and finally in 1997 (before his ordination as a bishop]]) Archdeacon of Stoke. While archdeacon he chaired the North Staffordshire Faiths in Friendship. He was a member of the General Synod of the Church of England from 1999.
In December 2001 he was consecrated a bishop by George Carey at Westminster Abbey, becoming the Bishop of Shrewsbury (one of the suffragan sees in the Diocese of Lichfield). He was chair of the Shropshire Strategic Partnership from 2006–2009. and was a member of the Rural Bishops' Panel from 2006–2009. In 2002 he completed his PhD as an external student of the University of Wales (Bangor). For Lent 2006 Smith committed himself to living on the minimum wage.
His election as Bishop of St Albans by the College of Canons of the Cathedral took place on 13 February 2009, and the confirmation of his election (a legal ceremony with Rowan Williams, Archbishop of Canterbury) followed on 31 March. Smith's inauguration took place on 19 September 2009.
From 2009 to 2011 he was joint chairman of the Anglican Methodist Working Party on the Ecclesiology of Emerging Expressions of Church which produced the report Fresh Expression in the Mission of the Church (2012). For the centenary of the newly reconfigured Diocese of St Albans in 2014 he wrote Saints and Pilgrims in the Diocese of St Albans (2013).
On 4 November 2013 he took his seat in the House of Lords as one of the Lords Spiritual. He has spoken on a wide range of subjects in Parliament with a particular focus on rural, agriculture, housing, welfare and problem gambling. He is President of the Rural Coalition.
In 2010, Smith was awarded an honorary Doctor of Divinity (DD) degree by the University of Birmingham.
He has contributed chapters to Changing Rural Life (2004) and Celebrating Community: God's Gift for Today's World (2006). He has written Growing up in Multi-faith Britain: Explorations in Youth, Ethnicity and Religion (2007), God-Shaped Mission: A Perspective from the Rural Church (2008), and co-authored The Reflective Leader (2011). He was joint editor of Faith and the Future of the Countryside (2012).The Reverend Alan Smith (1981–1997)
The Venerable Alan Smith (1997–2001)
The Right Reverend Alan Smith (2001–2002)
The Right Reverend Doctor Alan Smith (2002–present)