In a surprise announcement from his studio window to faithful standing below in St Peter’s Square, Francis said the churchmen will be elevated to a cardinal’s rank in a ceremony on November 28.
Francis asked for prayers so the new cardinals “may help me in my ministry as bishop of Rome for the good of all God’s faithful holy people”.
The selection of Gregory won praise from LGBTQ advocates in the United States, days after Pope Francis grabbed headlines for voicing support for civil unions for gay couples.
Other new cardinals include an Italian who is the long-time papal preacher at the Vatican, the Rev. Raniero Cantalamessa, a Franciscan friar; Kigali Archbishop Antoine Kambanda; Capiz Archbishop Jose Feurte Advincula, and Santiago Archbishop Celestino Aos.
Another Franciscan who has been elevated is Friar Mauro Gambetti, in charge of the Sacred Convent in Assisi.
The Pope, when elected in 2013, chose St Francis of Assisi as his namesake saint and earlier this month the pontiff visited the hill town in Umbria to sign an encyclical, or important church teaching document, about brotherhood.
Mr Gambetti was so surprised that at first he thought the Pope was joking when he heard he was named, convent spokesman the Rev Enzo Fortunato said.
He quickly pledged to “put himself at the service of humanity at a time so difficult to us all”, including offering compassion to the needy.
In a reflection of the Pope’s stress on helping those in need, especially the poor, Francis also named the former director of the Rome Catholic charity, Caritas, the Rev Enrico Feroci, to be a cardinal.
The prestigious Washington archdiocese traditionally brings elevation to cardinal’s rank so the appointment of Mr Gregory, 73, last year by the Pope had positioned him to be approached for the honour.
When Mr Gregory headed the Atlanta diocese earlier in his career, he wrote positively in a column about his conversations with Catholic parents of LGBTQ children.
An advocate for LGBTQ Catholics, Francis DeBernardo, said choosing Mr Gregory for a cardinal’s post signals Francis wants “LGBTQ people to be part of the church, and he wants church people to respect them”.
Mr DeBernardo linked the appointment to Francis’ recently reported comments supporting civil unions for same-sex couples.
He also praised the elevation to cardinal’s rank of a Vatican bishop who comes from Malta, a tiny, traditionally Catholic nation which has made significant progress in LGBTQ civil rights and protections in recent years.
Mr DeBernardo was referring to Mario Grech, 63, who serves at the Vatican as secretary general of the Synod of Bishops office and who formerly headed the diocese on the Maltese island of Gozo.
Nine of the new cardinals are younger than 80 and thus eligible to elect the next pontiff in a secret conclave.
No details were immediately given by the Vatican about the formal ceremony to make the churchmen cardinals, especially in view of travel restrictions involving many countries during the Covid-19 pandemic.
Others receiving the honour include Monsignor Marcello Semeraro, an Italian serving as prefect of the Vatican office that runs the saint-making process; Bishop Cornelius Sim, apostolic vicar of Brunei; the Italian archbishop of Siena and nearby towns in Tuscany, Augusto Lojudice; the retired bishop of San Cristobal de las Casas, Monsignor Felipe Arizmendi Esquivel, and an Italian former Vatican diplomat, Archbishop Silvano Tomasi.