My primary source of information is "The History of the Laestadian or Apostolic Lutheran Movement in America" by Uuras Saarnivaara. The account reads somewhat like a hagiography but I have chosen to give it the benefit of the doubt in most of its claims.
Lars Levi Læstadius was born on October 1st, 1800 in Swedish Lapland near Arjeplog. He was partly of Sami ancestry and was born into a family which had a history of pastoral ministry. Læstadius received his first ministerial training from his older brother Karl Erik who was a pastor in Lapland. He also had an intense interest in botany, which he studied at Uppsala University, where he proved to be a brilliant student. Læstadius decided to study theology and was ordained in 1825. He first pastored in Arjeplog where he married a local Sami woman, Brita Cajsa Alstadius, with whom he had twelve children. He soon moved to Kaaresuvanto, close to the Finnish border. At that time Lapland was nominally Christian. Drunkenness and immorality were common and the Finnish settlers only increased the corruption by their sale of liquor and their dishonesty.
When Læstadius became pastor of Kaaresuvanto, he performed the regular duties of a minister but he had no faith, and was unconcerned even for the salvation of his own soul. In 1831 he became seriously ill and almost died and in 1838 his son, Levi, died. These experiences seem to have softened Læstadius' heart and prepared him for a true conversion to Christ. He began to see the miserable condition of his flock and began an energetic struggle against the use of alcohol, which seemed to be the chief cause of misery in Kaaresuvanto. He struggled in vain by his own power to better the condition of his flock but no real results were achieved.
In the winter of 1844, Læstadius went to the Osele district of Lapland where he met a group of people called the "Readers." The Readers were a pietistic revivalist movement who, like John Wesley, had been influenced by the Moravians. There he met a Sami woman named Milla Clementsdotter who told him of her conversion to Christ. It was at this time that Læstadius seems to have first been converted. He wrote, "Only then I understood and saw the way of life. It had been hidden from me until I talked with Milla. Her simple story of her wanderings and experiences made a deep impression on my heart, and the light was revealed to me. I experienced the foretaste of heaven that evening which I spent with Milla."
Læstadius brought a new zeal to his parish. His sermons became straitforward, relentless calls to repentance. An example of Læstadius' new preaching, where he confronted his parishioners boldly, can be found in a sermon preached in 1857 where he says, "The drunkard’s favorite god is the visible flowing liquor, rum, or whatever his name may be, which we call the devil’s shit, for the devil teaches people to ruin God’s grain and to make it harmful to body and soul. The people who drink it become animals." Later in the same sermon is a powerful proclamation of the gospel: "Therefore, give God the glory, doubting and heavy-laden souls, and you will be allowed to see the brightness of God’s glory. Believe as a sinner and glorify the Lord Jesus with your confession, and with an unveiled face you will be allowed to view the brightness of the Lord’s glory and those glorious mansions in the kingdom of glory. Believe and glorify by your confession the King of Zion, who has won the kingdom with his bloody warfare. And into this kingdom he calls all penitent harlots, publicans, whores and thieves, those whom self-righteousness has condemned to hell, those oppressed by the law, those heavy-laden with the burden of sin and those who are laboring. He sends his servants to call the good and the bad to the joyous wedding that he has prepared in this kingdom."
Læstadius proclaimed the good news of the crucified "bloody Savior" and of the grace and forgiveness in his atoning and redeeming work. The laity were surprised at the change in their pastor. Some mocked him but many were convicted of the need for salvation. After a year of his new preaching of repentance, a Sami woman began to praise the Lord in a loud voice in the normally reserved church-service. She was Læstadius' first convert. At that same moment, an earthquake was felt. Læstadius understood the earthquake as a sign from God. After this event, many others began to powerfully experience the working of the Holy Spirit. They began to praise God, leap and clap their hands in church. They began to exhort unbelievers to repent and many began to receive visions. There were also manifestations, called "liikutukset" in Finnish, not unlike those reported in American revivals, where people would cry and wail loudly and roll on the ground.
The revival began to spread from Kaaresuvanto to the neighboring parishes in Sweden, Finland and Norway. As a result of growing family and economic difficulties, Læstadius was forced to move to another parish further to the south. In 1849, Læstadius preached his farewell sermon in Kaaresuvanto. Hundreds wept during the service and a miracle seems to have occured at this service, during the height of the revival. Water began to flow from the altar. Several young men climbed to the roof to find the source of the water but none was found. Said one of those who witnessed the miracle: "God gave us, thirsty whelps of grace, a clear sign that He will graciously let rivers of living water flow into our hearts from Jesus."
Læstadius moved to Pajala. There he received much opposition. Complaints were made to the governor and to the consistory where Læstadius was accused of preaching "brimstone" sermons and of causing congregants to fall into the disrupting "liikutukset." To avoid annoying the unconverted, two services were held, one for the converted who easily fell into "liikutukset" and one for the unconverted. Despite the opposition, the revival continued to spread largely through the work of lay preachers. Læstadius wrote sermons for these lay preachers and sent them to areas where he could not go.
In the last period of his life, Læstadius remained in the background of the revival. His "disciples," the lay preachers, were now doing most of the work including preaching their own sermons. Læstadius died on February 21, 1861. When he felt death approaching he said, "The Savior comes to receive me with open arms, and guests from heaven come to take me to be with them."
Lapland was a changed place when Læstadius died. Alcoholism had once been an epidemic among the Sami and the settlers. Prior to the revival, about 6000 gallons of liquor were consumed every year in the Jukkasjärvi parish. In 1850, not one drop of liquor was to be found in the whole parish. Among the 2500 people of the Tornio district of Lapland, there were in 1853, only two persons who habitually used alcohol. Vanity among the rich decreased, women sold their jewelry and gave the money to the poor and literacy was also greatly increased. According Saarnivaara, all of these outward changes were unimportant compared to the fact that, "hearts were turned to God and experienced God's grace, which made new men of sinners. They had peace and joy in Christ in their hearts, and they sought those things that are from above."