Moroni was appointed chief captain over all the Nephite armies at the age of twenty-five, around 74 BC, taking command of their wars during a period of conflict with the Lamanites and of internal division at home (Alma 43:16-17).
As a commander he armed his soldiers with breastplates, arm-shields, head-shields, and thick clothing, so that Zerahemnah’s larger but unarmored army was afraid to face them (Alma 43:19-21). At the city of Mulek he held a council of war and, unable to draw the Lamanites onto open ground, used Teancum to decoy them out while he took the city from the rear and trapped their force between his men and Lehi’s (Alma 52:19–40). He repeatedly halted his men once a battle was won and offered terms: he told Zerahemnah he did not desire to shed blood and would spare the Lamanites if they gave up their weapons and went home (Alma 43:54; Alma 44:1, 6), and he refused to fall on a drunken Lamanite army, saying he did not delight in bloodshed but in saving his people (Alma 55:19).
He made the “title of liberty” by tearing his coat and writing on it “In memory of our God, our religion, and freedom, and our peace, our wives, and our children,” fastening it to a pole and calling the people to covenant to maintain their rights and their religion (Alma 46:12-20). His epistle to the chief judge Pahoran rebuked the government for sitting still while his armies starved and threatened to come against those who sought to usurp power (Alma 60:23–24). When Pahoran replied that he had been driven from the judgment-seat by the king-men and was not offended by the rebuke, Moroni gave him his support (Alma 61:9).
Moroni prayed for the cause of the Christians and for liberty to rest on his people (Alma 46:13-16), and told Zerahemnah that the Nephites prevailed because of their faith in Christ and that God would preserve them so long as they were faithful (Alma 44:3-4). In his epistle he pledged that God’s blessing and strength would remain on the freemen who showed a spirit of freedom (Alma 60:25-27). Of him it was written that if all men had been like Moroni, the powers of hell would have been shaken forever and the devil would never have had power over human hearts (Alma 48:17). Mormon compared him to Ammon, the sons of Mosiah, Alma, and his sons, declaring that “they were all men of God” (Alma 48:18).
Around 57 BC Moroni gave up command of the armies to his son Moronihah and retired to his own house to spend the rest of his days in peace (Alma 62:43). He died in the thirty-sixth year of the reign of the judges, about 56 BC (Alma 63:3).