[2] From a very early age, Ironside showed a strong interest in evangelical Christianity, and was active in the Salvation Army as a teenager before later joining the "Grant" section of the Plymouth Brethren.

The family then moved to Los Angeles, California, on December 12, 1886, and as they found no Sunday school there to attend, young Harry started his own at age 11.

In 1889, after a visit from evangelist Donald Munro, Ironside became convinced that he was not "born again", and so gave up preaching at his Sunday school, spending the next six months wrestling with this spiritual problem.

[6] Ironside graduated from the eighth grade, began working as a part-time cobbler, and decided he had enough education (he never attended school again, a decision he later regretted).

[6] During the daytime, young Ironside worked full-time at a photography studio, and at night he preached at Salvation Army meetings, becoming known as the "boy preacher".

[8] At 18, the grueling schedule had taken its toll on his health, and Ironside resigned his commission, entering the Beulah Rest Home to recuperate.

[10] While there, he began helping at British evangelist Henry Varley's meetings and there met pianist Helen Schofield, daughter of a Presbyterian pastor in Oakland, California.

In 1914, he rented a storefront and established the Western Book and Tract Company, which operated successfully until the Depression in the late 1920s.

In 1918, he was associated with evangelist George McPherson; and in 1924, Ironside began preaching under the direction of the Moody Bible Institute.

In 1926, he was invited to a full-time faculty position at the Dallas Theological Seminary, an offer he turned down, although he was frequently a visiting lecturer there from 1925 to 1943.

After preaching a series of sermons at the Moody Church in Chicago, Ironside was invited in 1929 to serve a trial year as pastor.

In his book Wrongly Dividing the Word of Truth, he critiqued ultradispensationalist beliefs such as that the church in the book of Acts is different from the body of Christ, that the church did not start until Paul's imprisonment in Rome and that Baptism and the Lord's Supper no longer apply to Christians.

Despite his lack of formal education, his mental capacity, photographic memory and zeal for his beliefs caused him to be called "the Archbishop of Fundamentalism".

[28] Ironside was one of the most prolific Christian writers of the 20th century and published more than 100 books, booklets and pamphlets, a number of which are still in print.