Hanna Alwan joined the MLM and made his religious vows in 1979. On 18 July 1981 Alwan received his priestly ordination. The Synod of the Maronite Church elected him on 6 June 2011 Curial Bishop of Antioch. Pope Benedict XVI confirmed his appointment and named him on 13 August 2011 titular bishop of Sarepta dei Maroniti.