Daniel Woodall was born on June 1, 1841, in Dover, Delaware. Woodall worked as a civil engineer when the American Civil War erupted. Volunteering for the 1st Delaware Infantry Regiment, a volunteer unit mustered for 3 months of service in early 1861, he was commissioned a second lieutenant of Company H. When the regiment's enlistment term ended in August it was rebuilt in Wilmington for a service time of 3 years. As the regimental officers were to be appointed again Woodall was named Captain of Company F on September 28, 1861. The regiment was assigned to the II Corps of the Army of the Potomac; for service in the Eastern Theater. Leading his men into the Battle of Antietam on September 17, 1862, Woodall was shot in the arm. After the Battle of Fredericksburg Woodall was promoted to major on December 30, 1862.