Following his return to the Netherlands, he served as pastor of the parish of Blessed Sacrament in The Hague (1966–1970) and chaplain in the Red Cross Hospital.

[4] A former president of the Dutch Bishops' Conference, Simonis was a major supporter of Pope John Paul's visit to the Netherlands in 1985.

Simonis continued to govern the archdiocese as Apostolic Administrator until his successor, Wim Eijk, who was appointed on 11 December of the same year, took possession of the see on 28 January 2008.

[7] In 2011, Simonis testified on 25 January that he had no role in the appointment or dismissal of a Catholic priest accused of drugging and raping a young man.

The victim, Dave ten Hoor, says he was drugged and raped twice by the priest, identified only as Father Jan N., in 1989 and 1990 in the southern town of Terneuzen.

Simonis was drawn into the case because before moving to Terneuzen, Father Jan also allegedly abused children at a youth centre run by the Salesian order in Rijswijk, a town just outside The Hague.

[8] According to Radio Netherlands World: The cardinal was told by the then bishop of Rotterdam, Philippe Bär, that the priest had sexually abused underage boys in his parish in Zoetermeer.

Hanneke Brunt, whose altar-boy son was abused: "Simonis told me – 'This doesn’t go on in the Roman Catholic Church.