Alma, called Alma the Younger, was the son of Alma the Elder, the high priest who had fled the court of King Noah and established the church in the land of Zarahemla. Around 100 to 73 B.C. he served as the first chief judge of the Nephites and as high priest over the church, his father having conferred the office of high priest on him and given him charge over the affairs of the church (Mosiah 29:42).
In his youth Alma opposed the church his father led. Numbered among the unbelievers with the sons of Mosiah, he was “a very wicked and an idolatrous man” who used flattery to lead people into sin and went about secretly seeking to destroy the church of God (Mosiah 27:8-10). As they were rebelling, an angel appeared to Alma and his companions, spoke with a voice that shook the earth, and commanded Alma to stop persecuting the church. Alma fell to the earth, became dumb and unable to move, and was carried to his father; after the priests fasted and prayed two days and nights he recovered his speech and declared his repentance (Mosiah 27:11-17). He spoke of this conversion as God changing his people’s hearts and awakening them from a deep sleep (Alma 5:7).
As chief judge, Alma presided over the trial of Nehor, who had killed Gideon and taught for priestcraft. Nehor was condemned to die under the law given by Mosiah and was executed on the hill Manti after acknowledging that his teaching was contrary to the word of God (Alma 1:14-15).
In the ninth year of the reign of the judges, Alma delivered the judgment seat to Nephihah, while retaining the office of high priest, so that he could preach against the pride, craftiness, and contentions among his people (Alma 4:16-20). He then addressed the church in Zarahemla (Alma 5) and the church in the city of Gideon (Alma 7).
At Ammonihah Alma was rejected and persecuted (Alma 9; 14). With his companion Amulek he was imprisoned; their bonds broke, the prison walls collapsed and killed those who had struck them, and the two came out unharmed (Alma 14:26-29). Among those they taught was Zeezrom, a lawyer who had opposed them and whom Alma afterward baptized (Alma 15:12). Alma also confronted Korihor, who denied Christ until he was struck dumb and wrote that the devil had deceived him and that he had always known there was a God (Alma 30).
Alma taught faith through the comparison of the word to a seed, along with repentance, the resurrection, the judgment, and the atonement of Christ (Alma 32). He expounded the plan of redemption, the resurrection, the priesthood, and the scriptural basis for his teaching (Alma 12-13; 40-42).
Alma entrusted his son Helaman with the sacred records and commanded him to keep a record of the people on the plates of Nephi (Alma 37). Soon after, Alma departed and was not heard from again; the saying went abroad in the church that he was taken up by the Spirit or buried by the hand of the Lord, as Moses had been, and the record states that nothing is known of his death and burial (Alma 45:19).