Born in the Netherlands, Father Chappin entered the Society of Jesus in 1961 and was ordained to the priesthood in 1976. A history professor and archivist at the Pontifical Gregorian University, he became the archivist of the Secretariat of State’s Section for Relations with States in 1996.

Pope St. John Paul II named Father Chappin a consultor to the Congregation of the Causes of Saints (1991), consultor to the Pontifical Commission for the Cultural Heritage of the Church (1991), and a member of the Pontifical Committee of Historical Sciences (2004). Pope Benedict XVI named him vice prefect of the Vatican Secret Archive in 2007, from which he retired in 2012. The following year, Pope Francis again named him a consultor to the Congregation of the Causes of Saints.

The Vatican Secret Archive (since renamed the Vatican Apostolic Archive) published a volume of essays in Father Chappin’s honor for his 70th birthday.