Erastus Bernard Tyler was born in West Bloomfield, New York on April 24, 1822. He was the son of Asahel Tyler and Maria Bernard Tyler. In 1830, Tyler's family relocated to Ravenna, Ohio. Tyler attended local schools, before graduating from Granville College (now Denison University). As a young man, Tyler worked as a hat maker in Ravenna and as a fur trader in western Virginia.

While residing in Ravenna, Tyler was a member of the local militia, rising to the rank of brigadier general. When the American Civil War began, he helped to recruit the 7th Regiment of Ohio Volunteer Infantry, which included a company known as Tyler's Raiders. The unit's officers held Tyler in such high esteem that they elected him as the regiment's first colonel.

The 7th OVI was sent to western Virginia in August 1861, where Tyler and his men suffered an inauspicious introduction to combat. On August 26, Confederate Brigadier-General John B. Floyd launched a surprise attack against Tyler's encampment and inflicted a sound defeat upon the Yankees at the Battle of Kessler's Cross Lanes.

On May 14, 1862, Tyler became a brigadier-general and assumed command of the 3rd Brigade of Major General James Shields's 1st Division of the V Corps of the Army of the Potomac. In that capacity, Tyler saw action throughout most of the Shenandoah Valley Campaign of 1862, including the Battle of Kernstown I and the Battle of Winchester I. He was the principal Union field commander during the Federal loss at the Battle of Port Republic, the last engagement of the campaign. In September 1862, Tyler was present at the Battle of Antietam, but his brigade remained in reserve. In December, Tyler led his brigade in a series of unsuccessful assaults against Marye's Heights during the Union defeat at the Battle of Fredericksburg. In the course of the battle, Tyler was wounded in the head and torso by shrapnel from an exploding shell. After recuperating, Tyler ended the campaign season by participating in Major General Ambrose Burnside's infamous Mud March during January 1863.

When campaigning resumed in 1863, Tyler's brigade helped to stabilize the right flank of the Union line at the Battle of Chancellorsville until the Rebels prevailed. Soon after the battle, three of Tyler's four regiments mustered out of the service because their enlistments had expired. Left without a command, Tyler traveled to Washington D.C. to await assignment. In June, officials placed him in command of the defenses of Baltimore, Maryland. While there, he briefly succeeded Robert C. Schenck as commander of the VIII Corps from September 28, 1863 to October 10, 1863.

In July 1864, Tyler successfully defended the Jug Bridge on the Baltimore Pike with two regiments of inexperienced recruits during the Battle of Monocacy. President Lincoln later reportedly remarked that the Union was “more indebted to General Tyler than any other man for the salvation of Washington,” crediting the general for preventing Confederate General Jubal Early from entering the nation's capital.

When the war ended, officials brevetted Tyler to the rank of major general dating from March 1865. He mustered out of the service on August 24 of that year, and took up residence in Baltimore, Maryland, where he served as postmaster in 1877. On January 9, 1891, Tyler died at Baltimore due to intestinal complications from the wounds he received at Fredericksburg. He was buried at Greenmount Cemetery in Baltimore. After Tyler's death, his wife, Emily M. Tyler (who Tyler had met and married in Baltimore following the war), was awarded a pension for the general's service.

Erastus B Tyler