Archbishop-designate Jose Rodriguez Carballo, 59, will hold the number two post at the Congregation for Institutes of Consecrated Life and Societies of Apostolic Life, which is led by Brazilian Cardinal Joao Braz de Aviz.
The Spanish-born minister general of the Order of Friars Minor fills a post left vacant in October 2012 when U.S. Redemptorist Archbishop Joseph W. Tobin was appointed to lead the Archdiocese of Indianapolis.
Archbishop-designate Rodriguez's appointment comes as the congregation is wrapping up an apostolic visitation of women's religious orders in the United States. Begun in 2009, its aim was to study the community, prayer and apostolic life of the orders to learn why the number of religious women in the United States had declined so sharply since the 1960s.
The congregation has been reviewing and drawing up responses to the findings of the Vatican-appointed apostolic visitor as well as at least 400 other reports from the sisters who visited each community and from many of the communities themselves.
In a letter addressed to his brother Franciscans around the world, and released on the order's website when the Vatican announced his appointment April 6, Archbishop-designate Rodriguez said the nomination brought him both "joy and sadness."
Joy because it showed God's continued trust in him and because Pope Francis entrusted him with "a great responsibility to serve religious and consecrated life." He said it was also a sign of the pope's "confidence in me and the Order" of Friars Minor.
He added that he was sad to leave behind his fellow friars, their communal life and moments of prayer together.
However, "It comforts me to keep working for the life I love," both the life of a religious and Franciscan, he said in the letter.
In a similar letter to the Poor Clares, which includes all monasteries of cloistered nuns professing the Rule of St. Clare as well as the Sisters of the Annunciation and the Conceptionists, he said he believed "in the importance and necessity of your contemplative mission in the church and in the world."
"I believe in you, since I know the holiness that hides behind the walls of your monasteries. Count on me as I count on you," he wrote.
He said Italian Cardinal Tarcisio Bertone, Vatican secretary of state, was scheduled to be the principle consecrator at his episcopal ordination May 18, the eve of Pentecost, in Santiago de Compostela, Spain.
The archbishop-designate headed the Friars Minor since 2003, and since 2012 had been serving as president of the Union of Superiors General, the international organization for the heads of men's religious orders.
Born in Lodoselo, Spain, in 1953, he joined the Franciscans in 1970 and was ordained a priest seven years later at the age of 23, according to his biography on the order's website.
He studied at the Studium Biblicum Franciscanum in Jerusalem and the Pontifical Biblical Institute in Rome, then taught Scripture studies at the major seminary in Vigo, Spain, and for the theological faculty of Santiago de Compostela. He also taught theology of consecrated life and served as formation director for young religious.
He served as president of the Union of Franciscan Provincial Ministers of Europe from 1993 to 1997.
In 2003, he was elected Minister General of the Order of Friars Minor -- the 119th successor of St. Francis of Assisi. He was re-elected for another six-year term in 2009, overseeing about 15,000 Franciscans who work in 113 countries.
After his re-election, he told reporters Franciscans see their role as being guardians of hope, messengers of the culture of life, and bridge-builders linking cultures and religions.
Franciscans "cannot turn our backs on the world, especially on the poorest," he said, explaining that members of the order demonstrate their love for the world by being fully engaged in it, and by serving the needs of all people.
"The world is not just a battlefield; it is above all an opportunity to bring the Gospel to society" and God's love to all people, he added.
In a world suffering from human rights' violations, a global economic meltdown, environmental disaster in many regions and forced migration, the Gospel can provide responses, he said.