John Grimes was born on January 26, 1817, in Indiana to Thomas and Nancy Grimes. His father was a farmer who owned $1,200 of real estate by 1850. He married Mary Burkhart in Monroe County, Indiana, on March 12, 1840, and they had at least five children: Nancy, born around 1841; Henry, born around 1843; David, born around 1846; Sarah, born around 1847; and William, born around 1850. They lived in Johnson, Indiana, and his wife Mary died there of typhoid fever in 1850.
Grimes married Eliza Brummet (Barrow) on September 26, 1850, and they had at least six children: Emily, born around 1851; James, born around 1853; John, born around 1855; Ellen, born around 1857; and Walter, born around 1860. They moved to Whitebreast, Iowa, in the 1850s, and Grimes worked as a farmer. By 1860, he owned $1,800 of real estate and $780 of personal property.
He probably supported the Democratic Party during the Civil War. In November 1863, he thanked his sister Sarah, who apparently sympathized with his political viewpoint. As he explained, “I was glad to know that I had one Sister that woodent denounce me as a traiter becaus I dont indorse the acts of Abraham the first.” He denounced secessionists and abolitionists alike, insisting that they were “both violaters of the constitution of our country[.] I dont believe ther ever wold hav bin any Seceshionist had it not hav bin for the abolition party.”
Eliza died sometime in the 1860s, and he married Rachel Brown on January 7, 1869. By 1870, he owned $5,000 of real estate and $1,500 of personal property. He died in Iowa on April 13, 1899.