Joseph Camilleri has been actively involved in the Pax Christi movement since 1969. He served as General Secretary of Pax Christi in England in 1970-72, facilitated the establishment of Pax Christi in the United States, and was the founding President of Pax Christi in Australia from 1974, a position he held for over 30 years. He continues to serve on the Executive Committee of the Victorian branch.

Pax Christi was founded in Europe in 1945 as a Catholic reconciliation movement bringing together French and Germans after World War II. Today, the movement has more than 100 member organisations active in more than 50 countries and across five continents.