Upon his graduation in 1860, he was ordained as a Lutheran pastor, and served pastorates in New York, Indiana, and his home state of Ohio; his last pastorate was at Saint MatthewsEnglish Lutheran Church in Brooklyn, New York, where he stayed seven years. In 1872, Funk resigned from the ministry and made an extensive tour through Europe, northern Africa, and Asia Minor. Funk was a prohibitionist. He founded the Voice in 1880, an organ of the Prohibition Party, and he was the Prohibition candidate for mayor of New York. His Staten Island home, "grand in scale and extremely decorative", was built in 1893 in what was then Prohibition Park, and the home still stands. In 1875 he founded the publishing firm of I.K. Funk & Company, with the help of a Wittenberg classmate, Adam Willis Wagnalls, a lawyer and accountant. That year he founded and published the Metropolitan Pulpit. Missionary Review also numbered among the many religious publications he founded after 1876. In 1877 the name of his company was changed to Funk & Wagnalls Company, to reflect Wagnalls' partnership. In 1890 Funk published The Literary Digest, a departure from the religious works earlier in his career. Perhaps Funk's most important achievement was his Standard Dictionary of the English Language, the first volume of which was published in 1893. He worked with a team of more than 740 people. His aim was to provide essential information thoroughly and simply at the same time. In order to achieve this he placed current meanings first, archaic meanings second, and etymologies last. The dictionary was said to have cost Funk & Wagnalls over $960,000. From 1901 until 1906, Funk & Wagnalls compiled the Jewish Encyclopædia. After Funk died in 1912, the publishing house eventually became a subsidiary of Thomas Y. Crowell Co.
Psychic research
In his later years, Funk spent time on psychic research. Funk was a believer in spiritualism and in his book, The Widow's Mite and Other Psychic Phenomena, published in 1904, he defended a number of mediums and spirit photography. Magician Joseph Rinn has noted that Funk was easily duped by fraudulent mediums, such as the Bangs Sisters. Funk had bought several of their 'spirit' pictures, unaware they were produced fraudulently. He also defended Anna Eva Fay and May S. Pepper, two mediums that were also exposed.
Personal life
Funk married Eliza Thompson of Carey, Ohio in 1864. After her death in 1868, Funk married her sister, Helen Gertrude Thompson. Funk had two sons and a daughter:
James A. Funk, who predeceased his father in 1898 at age 21.
Lida M. Funk, a Vassar College graduate who married Robert Scott in 1895.
Funk died in Montclair, New Jersey on April 4, 1912. After some bequests to his alma mater and his brother, the residue of the estate was left to his two surviving children.
Selected works
The Complete Preacher, Sermons Preached By Some of the Most Prominent Clergymen
Great Advance: Address by Dr. I.K. Funk, as Chairman of the New York Prohibition State Convention. Saratoga, September 12, 1895