The 95-year-old Democrat used a walker to enter the Maranatha Baptist Church in Plains, Georgia, and spoke to more than 400 people.
With help, Mr Carter sat on a motorised lift chair at the front of the room to teach a 45-minute lesson based on the Old Testament book of Job.
"Morning, everybody," he said cheerfully.
Referring to a cancer diagnosis that resulted in the removal of part of his liver in 2015, Mr Carter said he was "at ease" with the idea of dying and believes in life after death.
He was briefly hospitalised and has since been recovering at home since fracturing his pelvis on 21st October.
Mr Carter is the oldest US ex-President ever and has been teaching Bible lessons since he was in his teens.
Rev Tony Lowden said Secret Service agents, relatives and fellow church members all discouraged Mr Carter from teaching because of the injury, but he insisted.
"He is pouring out that you might see Christ while he is suffering," Rev Lowden told the crowd.
Mr Carter remained for the worship service after teaching, sitting in a pew beside his wife, Rosalynn, and singing hymns with the congregation.
Referring to the former president and Jesus Christ by their initials, Rev Lowden gave thanks for Carter in prayer.
"The greatest thing I've learned as a pastor here is watching J.C. follow J.C.," he said.
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