Leasure held the rank of colonel in the IX Corps through most of the war. His regiment, the 100th Pennsylvania Infantry, was known as the "Roundheads" because it was recruited from descendents of the followers of Oliver Cromwell.
 The regiment first saw action in the command of Brig. Stevens at the Battle of Secessionville in South Carolina on June 16, 1862. Transferred to the Virginia theater of the war, Leasure participated in the Second Battle of Bull Run, and the Battle of Chantilly. Wounded at Second Bull Run he subsequently missed the Maryland Campaign. Moving to the Western Theater with the IX Corps, Leasure continued in brigade command under Maj.
John Parke during the Siege of Vicksburg and Blue Springs. Returning to command of the 100th Pennsylvania he took part in the Siege of Knoxville.Returning to Virginia, Leasure now commanded the 2nd Brigade, 1st Division in the IX Corps at the Battle of the Wilderness and the Battle of Spotsylvania. Stevenson was killed during the fighting at Spotsylvania, Leasure was the ranking subordinate and took command of the division for 3 days until relieved of this capacity by Maj. He was mustered out of the service on August 30, 1864. He received the brevet rank of brigadier general in 1865. Daniel Leasure, Colonel of the 100th (Roundhead) regiment, and Brevet Brigadier General, was born in Westmoreland county, on the 18th of March, 1819. His great-grandfather, Abraham Leasure, emigrated to Pennsylvania from the borders of Switzerland, near France, whither the ancestors of the family had fled after the massacre of St. Bartholomew, they being Huguenots of Nayarre. He studied medicine, and graduated at Jefferson Medical College. He was married in September, 1842, to Isabel W. Eldest daughter of Samuel Hamilton, for several years a member of the Pennsylvania Legislature. He had served in the militia, and, at the opening of the rebellion, raised a company, and was made Adjutant, and also Acting Assistant Adjutant General of the brigade upon the staff General Negley. At the close of the three-months' term, he was authorized to raise a veteran regiment. Lawrence county, where he had taken up his residence, had been largely settled by the descendants of those who had followed Cromwell in the struggles of the English people for liberty, and from among them he drew recruits, appropriately designating it the "Roundhead" regiment.
Colonel Leasure was the first sent to the department of the South, where his command formed part of the brigade of General Isaac I. In the attack upon Tower Fort, near Secessionville, on the morning of the 16th of June, 1862, Colonel Leasure led the brigade, and won the commendation of General Stevens. Residence Lawrence County PA; a 42 year-old Physician. Enlisted on 4/25/1861 as a 1st Lieutenant.
On 4/25/1861 he was commissioned into Field & Staff PA 12th Infantry. He was Mustered Out on 8/5/1861 at Harrisburg, PA. On 8/31/1861 he was commissioned into Field & Staff PA 100th. He was Mustered Out on 8/30/1864.
Wounded 8/29/1862 2nd Bull Run, VA. Wounded 5/12/1864 Spotsylvania Court House, VA. 1st Lieut 4/25/1861 (1st Lieut & Adjutant).Capt 7/1/1861 As of Co. Colonel 8/31/1861 (As of 100th PA Inf). Intra Regimental Company Transfers: from Field & Staff to company H. Born 3/18/1819 in Mt Pleasant, Westmoreland Co. Died 10/4/1886 in St Paul, MN.
Daniel Leasure graduated at Jefferson Medical College in 1846. He settled in New Castle in 1849, and practiced in the city successfully until the breaking out of the rebellion, when he organized two military companies in the vicinity. He was shortly afterwards promoted to a colonelcy, and served with distinction during the entire war, at the close of which he was breveted brigadier-general. He then practiced a few years in this city, removing, in 1870, to Allegheny City. The item "Civil War CDV Union Colonel Daniel Leasure 100th Pennsylvania Volunteers" is in sale since Friday, December 7, 2018.This item is in the category "Collectibles\Militaria\Civil War (1861-65)\Original Period Items\Photographs". The seller is "civil_war_photos" and is located in Midland, Michigan. This item can be shipped worldwide.