Sherman was born in Lancaster, Ohio, to Charles Robert Sherman and his wife, Mary Hoyt Sherman, the eighth of their 11 children.
John Sherman's grandfather, Taylor Sherman, a Connecticut lawyer and judge, first visited Ohio in the early nineteenth century, gaining title to several parcels of land before returning to Connecticut.
After Taylor's death in 1815, his son Charles, newly married to Mary Hoyt, moved the family west to Ohio.
Several other Sherman relatives soon followed, and Charles became established as a lawyer in Lancaster.
By the time of John Sherman's birth, Charles had just been appointed a justice of the Supreme Court of Ohio.

Sherman's father died suddenly in 1829, leaving his mother to care for 11 children.
Several of the oldest children, including Sherman's older brother William, were fostered with nearby relatives, but John and his brother Hoyt stayed with their mother in Lancaster until 1831.
In that year, Sherman's father's cousin (also named John Sherman) took Sherman into his home in Mount Vernon, Ohio, where he enrolled in school.
The other John Sherman intended for his namesake to study there until he was ready to enroll at nearby Kenyon College, but Sherman disliked school and was, in his own words, "a troublesome boy".
In 1835, he returned to his mother's home in Lancaster.
Sherman continued his education there at a local academy where, after being briefly expelled for punching a teacher, he studied for two years.

In 1837, Sherman left school and found a job as a junior surveyor on construction of improvements to the Muskingum River.
Because he had obtained the job through Whig Party patronage, the election of a Democratic governor in 1838 meant that Sherman and the rest of his surveying crew were discharged from their jobs in June 1839.
The following year, he moved to Mansfield to study law in the office of his older brother, Charles Taylor Sherman.
He was admitted to the bar in 1844 and joined his brother's firm.
Sherman quickly became successful at the practice of law, and by 1847 had accumulated property worth $10,000 and was a partner in several local businesses.
By that time, Sherman and his brother Charles were able to support their mother and two unmarried sisters, who now moved to a house Sherman purchased in Mansfield.
In 1848, Sherman married Margaret Cecelia Stewart, the daughter of a local judge.
The couple never had any biological children, but adopted a daughter, Mary, in 1864.

Around the same time, Sherman began to take a larger role in politics.
In 1844, he addressed a political rally on behalf of the Whig candidate for president that year, Henry Clay.
Four years later, Sherman was a delegate to the Whig National Convention where the eventual winner Zachary Taylor was nominated.
As with most conservative Whigs, Sherman supported the Compromise of 1850 as the best solution to the growing sectional divide.
In 1852, Sherman was again a delegate to the Whig National Convention, where he supported the eventual nominee, Winfield Scott, against rivals Daniel Webster and incumbent Millard Fillmore, who had become president following Taylor's death.
Sherman was born in Lancaster, Ohio, to Charles Robert Sherman and his wife, Mary Hoyt Sherman, the eighth of their 11 children. John Sherman's grandfather, Taylor Sherman, a Connecticut lawyer and judge, first visited Ohio in the early nineteenth century, gaining title to several parcels of land before returning to Connecticut. After Taylor's death in 1815, his son Charles, newly married to Mary Hoyt, moved the family west to Ohio. Several other Sherman relatives soon followed, and Charles became established as a lawyer in Lancaster. By the time of John Sherman's birth, Charles had just been appointed a justice of the Supreme Court of Ohio.
Sherman's father died suddenly in 1829, leaving his mother to care for 11 children. Several of the oldest children, including Sherman's older brother William, were fostered with nearby relatives, but John and his brother Hoyt stayed with their mother in Lancaster until 1831. In that year, Sherman's father's cousin (also named John Sherman) took Sherman into his home in Mount Vernon, Ohio, where he enrolled in school. The other John Sherman intended for his namesake to study there until he was ready to enroll at nearby Kenyon College, but Sherman disliked school and was, in his own words, "a troublesome boy". In 1835, he returned to his mother's home in Lancaster. Sherman continued his education there at a local academy where, after being briefly expelled for punching a teacher, he studied for two years.
In 1837, Sherman left school and found a job as a junior surveyor on construction of improvements to the Muskingum River. Because he had obtained the job through Whig Party patronage, the election of a Democratic governor in 1838 meant that Sherman and the rest of his surveying crew were discharged from their jobs in June 1839. The following year, he moved to Mansfield to study law in the office of his older brother, Charles Taylor Sherman. He was admitted to the bar in 1844 and joined his brother's firm. Sherman quickly became successful at the practice of law, and by 1847 had accumulated property worth $10,000 and was a partner in several local businesses. By that time, Sherman and his brother Charles were able to support their mother and two unmarried sisters, who now moved to a house Sherman purchased in Mansfield. In 1848, Sherman married Margaret Cecelia Stewart, the daughter of a local judge. The couple never had any biological children, but adopted a daughter, Mary, in 1864.
Around the same time, Sherman began to take a larger role in politics. In 1844, he addressed a political rally on behalf of the Whig candidate for president that year, Henry Clay. Four years later, Sherman was a delegate to the Whig National Convention where the eventual winner Zachary Taylor was nominated. As with most conservative Whigs, Sherman supported the Compromise of 1850 as the best solution to the growing sectional divide. In 1852, Sherman was again a delegate to the Whig National Convention, where he supported the eventual nominee, Winfield Scott, against rivals Daniel Webster and incumbent Millard Fillmore, who had become president following Taylor's death.
John Sherman