Walther born the son of a pastor in Langenchursdorf in the Kingdom of Saxony (part of modern-day Germany). In October 1829, he enrolled at the University of Leipzig to study theology. He had to take six months off from the university due to a nearly-fatal lung disease; during the time off he acquainted himself with the works of Martin Luther, and became convinced of their theological rectitude, especially in regards to his position on the confessional.
On January 15, 1837, he was ordained as a pastor in the town of Bräunsdorf, Saxony. However, he became increasingly at odds with the government of Saxony, whose interpretation of Lutheranism he saw as a deviation from the original vision of Luther. In November 1838 he joined with another Pastor of similar views, Martin Stephan from Dresden, and left Saxony for the United States, along with 800 other Saxon immigrants, to gain the freedom to practice his religious beliefs. The ship arrived January 5, 1839 in New Orleans, and most of the immigrants (including Walther) settled in the area of St. Louis. Stephan was initially the religious leader (and self-proclaimed bishop) of the new settlement, but he soon became embroiled in charges of corruption and sexual misconduct, and was expelled from the settlement, leaving Walther as the senior clergyman.
During this period there was considerable debate within the settlement over the proper role of the church in the New World: whether it was a new church, or remained within the German Lutheran hierarchy. Walther's view that they could consider themselves a new church prevailed, and in May 1841 he became Pastor of Trinity Lutheran Church, a position he held until his death.
During his forty years of involvement in the church, Walther held several positions, including president of Concordia Seminary, St. Louis, (founded at Perry County, Missouri in 1838), founder of the St. Louis Lutheran Bible Society (1853), and founder and editor of several periodicals. He also wrote several important books on theology, including The Proper Distinction Between Law and Gospel.
Walther also vigorously resisted the influence of the major secular philosophies and movements of his day. Concerning Humanism, he wrote:
"It is an irrefutable fact that humanism has not only supplanted Christianity among a large part of the current population, it has also infected Christian theology in its very inner core, has poisoned and weakened it. We define humanism as the belief in a human ideal, a belief that man within himself has the ability to develop into a state of completeness and achieve happiness." ["Slavery, Humanism and the Bible"]
He died in St. Louis on May 7, 1887, and was buried at Concordia Cemetery, where a mausoleum was later built in his honor.
Walther's goal was to strive to be faithful to the Scriptures and the Lutheran Confessions. He was constantly aware that he was standing on the shoulders of the giants who had come before him. Those who oppose the Lutheran Church and reject its teachings, or are merely curious and interested in understanding it better, will often ask: "Where was the Lutheran Church before Martin Luther?" Here is the answer that C.F.W. Walther provides in his superb essay, "Concerning the Use of the Name Lutheran," printed in serial form for the first several issues of his newspaper Der Lutheraner, that is, The Lutheran.
So long as there has been an orthodox church on earth, there has also been the Lutheran Church. She is (as strange as that sounds) as old as the world, for she has no other doctrine than the patriarchs, prophets and apostles had received from God and preached. Certainly the name Lutheran first arose 300 years ago, but not what is signified by the name. So as often, therefore, as the question is to put to us: 'Where was the Lutheran church before Luther?' it is so easy to answer: She was everywhere that there were Christians, who believed in JESUS Christ and his holy Word from their hearts, and would not let themselves be dissuaded from this faith, which alone saves, by any human institutions or who finally in their tribulation in death still also took their refuge in him.*
Walther's point is simply that the name "Lutheran" is what we use to distinguish the faith and confession of the one, catholic, apostolic church, from all its other forms in erring churches. In a sense there is no such thing as a "Lutheran Church" but when pressed to make clear what it is that God's Word teaches and proclaims, we therefore, to distinguish it from other options, refer to it as the Lutheran Church, but it is actually is nothing other than the good, old, faith once delivered to the saints.
* Source: CFW Walther, "Concerning the Name Lutheran" in Der Lutheraner, Sept. 23, 1844, (Vol. I, No. 2), p. 6. Translated by Joel Baseley.