On February 8, 1862, Radford accepted command of Cumberland.
He was aboard Roanoke as a member of a Naval Board of Inquiry March 8, 1862, when his ship was sunk by the Confederate ram Virginia during the Battle of Hampton Roads.

A Naval Board convened in April 1862 at the Naval Academy Preparatory School with Radford as a member.
 He received, June 10, 1862, temporary duty as Executive Officer of Brooklyn Navy Yard under command of Rear Admiral Hiram Paulding.
 The assignment stretched into almost two years of equipping and fitting-out hundreds of vessels for the Navy.
 Radford received promotion to captain July 16, 1862, and then to commodore April 24, 1863.

On May 15, 1864, Radford was directed to report to Rear Admiral John Dahlgren at Philadelphia for command of the armored ship New Ironsides.
Upon arrival it was determined the ship required repairs so Radford was relieved and ordered to a Naval Board in Washington, D.C. during July 1864.
He was recommitted to New Ironsides on August 16, 1864, and joined the North Atlantic Blockading Squadron at Hampton Roads.
Rear Admiral David Porter assembled a fleet to attack Fort Fisher for the control of Cape Fear River.
 He placed Radford in command of the Ironclad Division, consisting of flagship New Ironsides, Dictator, Monadnock, Canonicus, Saugus and Mahopac during attacks on Fort Fisher in December 1864 and in January 1865.
David Porter commended Radford's support for the Union forces ashore and eight members of his crew were awarded the Medal of Honor.

New Ironsides sailed January 24, 1865, up the James River to Bermuda Hundred to protect the stores of the Army of the Potomac from a threatened raid by Confederate rams during the siege of Petersburg.
 Radford took charge of the flotilla assembled there and coordinated with Generals Ulysses Grant and Edward Ord.
 Radford transferred his flag to Dumbarton when New Ironsides was sent to Norfolk Naval yard February 18, 1865, for repairs.
 With the end of war near, Dumbarton departed from the James River March 22, 1865, and officers and crew were detached upon arrival at the Washington Navy Yard.

On April 4, 1865, Radford sailed Phlox from Washington, D.C. up the James River and arrived at City Point, Virginia the next evening.
 From there, he conveyed Vice President Andrew Johnson and Preston King to Richmond, Virginia and back.
 President Abraham Lincoln was already in Richmond, unaccompanied by any of his Cabinet, to witness the downfall of the Confederate stronghold.
 He became agitated about the Johnson and King arrival and ordered Radford to keep both of his passengers elsewhere.
 While moored for two days, Radford discovered stepbrother Meriwether Clark was a prisoner of war and brought him aboard Phlox to await release.
On February 8, 1862, Radford accepted command of Cumberland. He was aboard Roanoke as a member of a Naval Board of Inquiry March 8, 1862, when his ship was sunk by the Confederate ram Virginia during the Battle of Hampton Roads.
A Naval Board convened in April 1862 at the Naval Academy Preparatory School with Radford as a member.  He received, June 10, 1862, temporary duty as Executive Officer of Brooklyn Navy Yard under command of Rear Admiral Hiram Paulding.  The assignment stretched into almost two years of equipping and fitting-out hundreds of vessels for the Navy.  Radford received promotion to captain July 16, 1862, and then to commodore April 24, 1863.
On May 15, 1864, Radford was directed to report to Rear Admiral John Dahlgren at Philadelphia for command of the armored ship New Ironsides. Upon arrival it was determined the ship required repairs so Radford was relieved and ordered to a Naval Board in Washington, D.C. during July 1864. He was recommitted to New Ironsides on August 16, 1864, and joined the North Atlantic Blockading Squadron at Hampton Roads. Rear Admiral David Porter assembled a fleet to attack Fort Fisher for the control of Cape Fear River.  He placed Radford in command of the Ironclad Division, consisting of flagship New Ironsides, Dictator, Monadnock, Canonicus, Saugus and Mahopac during attacks on Fort Fisher in December 1864 and in January 1865. David Porter commended Radford's support for the Union forces ashore and eight members of his crew were awarded the Medal of Honor.
New Ironsides sailed January 24, 1865, up the James River to Bermuda Hundred to protect the stores of the Army of the Potomac from a threatened raid by Confederate rams during the siege of Petersburg.  Radford took charge of the flotilla assembled there and coordinated with Generals Ulysses Grant and Edward Ord.  Radford transferred his flag to Dumbarton when New Ironsides was sent to Norfolk Naval yard February 18, 1865, for repairs.  With the end of war near, Dumbarton departed from the James River March 22, 1865, and officers and crew were detached upon arrival at the Washington Navy Yard.
On April 4, 1865, Radford sailed Phlox from Washington, D.C. up the James River and arrived at City Point, Virginia the next evening.  From there, he conveyed Vice President Andrew Johnson and Preston King to Richmond, Virginia and back.  President Abraham Lincoln was already in Richmond, unaccompanied by any of his Cabinet, to witness the downfall of the Confederate stronghold.  He became agitated about the Johnson and King arrival and ordered Radford to keep both of his passengers elsewhere.  While moored for two days, Radford discovered stepbrother Meriwether Clark was a prisoner of war and brought him aboard Phlox to await release.
William Radford