[1] He received a common school education and read law; he was admitted to the Ohio bar in 1857, by Justice Thomas W. Bartley, with the endorsement of Jacob Dolson Cox.

[1] At the outbreak of the American Civil War, Richardson immediately resigned as district attorney, and set about gathering a company of volunteers from Chippewa County.

[3]: 444 He was promoted to captain in February 1863,[4] and, at the time of the Battle of Gettysburg, he had been detailed from his regiment to serve on the brigade staff of General Solomon Meredith.

During the intense fighting on that first day of battle, Colonel Meredith was wounded, along with several of the other field officers of the brigade—Captain Richardson played an instrumental role in maintaining order and communication among the regiments during the critical retreat to Seminary Ridge.

As the Union line began to falter in the afternoon, Richardson picked up the colors of a Pennsylvania regiment—which had collapsed in panic—and tried to rally the men to stand together.

[4] Richardson's actions on the first day of Gettysburg were specifically mentioned in General Abner Doubleday's account of the battle in the Official War Records, Series 1, Volume 27, Part 1, Item 29.

[2]: 452 During the Battle of Five Forks, in the closing weeks of the war, Richardson personally saved the life of Major General Gouverneur K. Warren, and was wounded in the process.

[6] While there, he also was selected as a delegate to the 1868 Republican National Convention, and was an enthusiastic supporter of General Ulysses S. Grant's presidential campaign.

[7] During the first winter of the Civil War, in 1861, Richardson's commanding officer, Colonel William W. Robinson, brought his family to camp with the regiment in northern Virginia.