Ms Morffi addressed the issue in a statement on Friday:
"This weekend, I married the love of my life and, unfortunately, I was terminated from my job as a result," she wrote on her Instagram page.
"In their eyes, I'm not the right kind of Catholic for my choice of partner."
About 20 parents gathered at the school to demand answers and protest Ms Morffi's sacking, on Friday morning. They described Ms Morffi as a "great teacher" and said the school administration hadn't offered a satisfactory explanation as to why she was fired.
"We were extremely livid," Cintia Cini, a parent of one of the children in Ms Morffi's class, told the Miami Herald.
"They treated her like a criminal, they didn't even let her get her things out of her classroom."
Ms Cini said the parents hadn't known Ms Morffi was gay, but didn't care about her sexual orientation. "Our only concern was the way she was with our children, the way she taught our children and this woman by far was one of the best teachers out there," she said.
"You know, to be a Catholic, you're taught to be forgiving. But if you're gay, forget about it."
Ricardo Oviedo, another parent of a child in Ms Morffi's class, said "she maintained a high moral standard at school and was inscribing in our kids a sense of community and love".
Archbishop Thomas Wenski sent a memo to employees reminding them of the Archdiocese of Miami's policy after judges lifted Florida's ban on same-sex marriage in 2015. All employees, including school teachers, are considered church representatives and are expected to abide by Catholic teachings, the memo said. Any conduct "inconsistent" with that could result in disciplinary action, including termination.
Ms Morffi is considering legal action, according to her lawyer.