Charles was born in Clarendon, Vermont on June 12, 1808, the ninth of the ten children of Daniel and Susannah Olin Dyer.

In 1837, Dr. Dyer rented a hall and called a protest meeting in reaction to the murder of Elijah Lovejoy by a mob in Alton, Illinois.

[3] In 1839, Dyer took in a runaway slave boy, and arranged for his passage on to Windsor, Canada, thus beginning his career as a stationmaster on the Underground Railroad.

One prominent conductor on the Underground Railroad, Owen Lovejoy, is known to have taken many runaway slaves to Dr. Dyer's home, and was frequently a guest there himself.

Once the slave catchers recovered from their surprise at this bold action, they chased Dr. Dyer out into the street, and one of them charged him with a Bowie knife.

In 1863, Abraham Lincoln appointed Dr. Dyer a judge of the Mixed Court for the Suppression of the Slave Trade in Sierra Leone.