Hundreds of people arrived Thursday night at St. Raymond's Maronite Cathedral in St. Louis to welcome Wissam Akiki, who called it a "historic day."
Although Eastern Catholic churches in the Middle East and Europe ordain married men, the Vatican banned the practice in the U.S. in the 1920s.
Maronites are among more than a dozen of Eastern Catholic church groups in the U.S. that accept the pope's authority, but have their own rituals and liturgy. Previously, popes have made exceptions on an individual basis for some married men to become Eastern Catholic priests in the U.S.
"Almost half of our priests in Lebanon are married, so it's not an unusual event in the life of the Maronite church, though in the United States it is," said Deacon Louis Peters, chancellor at St. Raymond's.
Experts cautioned against reading too much into Akiki's ordination.
"This is certainly not an automatic indication that the mandate of celibacy within Roman rite will be overturned," said Randy Rosenberg, a theological studies professor at Saint Louis University.
Akiki, 41, emigrated from Lebanon in 2002. He has been married to his wife Manal for about 10 years. They have an 8-year-old daughter named Perla.
The Associated Press contributed to this report.