William Cummings Page was born into slavery in March 1831 in Norfolk, Virginia. He was owned by Andrew Stevenson of Albemarle County before the war. 

Page worked as a waiter and married Rebecca Page in a slave marriage sometime before the war. Their only child, Lewis Page, was born around 1858. Rebecca and Willaim separated during the course of the war. He enlisted in the 39th USCT Infantry Regiment on March 30, 1864, in Baltimore, Maryland, for a period of three years. At the time of his enlistment, he was 35 years old and stood 5 feet, 8 inches tall, with a mulatto complexion, black hair, and black eyes. He mustered in as a private in Company F that same day. Page's regiment was soon attached to the 1st Brigade, 4th Division, 9th Corps of the Army of the Potomac.

Page was sent to the general hospital in Annapolis, Maryland, on April 21,1864, but he returned to his regiment by May. He participated in the Overland Campaign from the Rapidan to the James River, Virginia, between May and June 1864. Page and the regiment were tasked with guarding the trains of the Army of the Potomac through the Wilderness to the Siege of Petersburg. 

Page and the regiment arrived in Petersburg between June 15-19. He was present for the Siege of Petersburg between June 16 and December 7. He fought in the Battle of the Crater on July 30, participated in actions against the Weldon Railroad on August 18-21, and took part in the Battle of Poplar Grove Church on September 29-30. He also saw action at Hatcher's Run on the Boydton Plank Plank Road on October 27-28. Following this action, the regiment was transferred to the Bermuda Hundred front of the Richmond-Petersburg line.

The army assigned the regiment to the 25th Corps for the first expedition to Fort Fisher, North Carolina, on December 7-27, followed by a second expedition on January 7-15, 1865. Page next saw combat at Sugar Loaf Hill on January 19. However, after this battle, Page went to the base hospital with an undisclosed illness, and he was not present for the regiment's continued push into southeastern North Carolina. He was admitted on February 11, 1865, the same day that the regiment fought in the Battle of Federal Point. However, in March of 1865, he had recovered enough to return to the regiment. 

Page was present for at least some of the Carolinas Campaign between March 1 and April 26. While records do not indicate exactly when he returned to the regiment, he returned during the period when the regiment was advancing on Kingston and Goldsboro, North Carolina, between March 6 and 21. The men continued to advance deeper into the countryside, fighting at Cox's Bridge on March 23-24, followed by an advance on Raleigh between April 9-14. They marched into the capital to occupy the city on April 14, the same day that President Abraham Lincoln was assassinated in Washington, D.C. Page and the regiment, now a part of the 10th Corps, continued to chase General Joseph Johnston's army around North Carolina until Johnston surrendered at Bennett Place on April 26, 1865. Following the surrender, Page saw duty at various points in the Department of North Carolina until December 4, 1865, when he mustered out in Wilmington, North Carolina.

Following the war, Page married his second wife Catherine Waters in Washington, D.C. Page then settled in Blenheim in Albemarle County, Virginia, where he worked as a farmer. Page and his wife had four children: William C., born October 27, 1868; Anna M., born September 11, 1872; Jonathan, born June 19, 1874; and James, born June 22, 1878. Page's son Lewis and his father Thomas lived with the family, as well. Page suffered from rheumatism of the legs, throat trouble, shortness of breath, impaired vision, and partial deafness. He first began receiving a pension of $12 a month in 1890, and by 1910, it had increased to $20. He died on May 26, 1910, in Blenheim. Following his death, his widow Catherine Page was able to get a pension, despite difficulty due to a marriage to a previous husband. She was receiving $30 a month by the time of her death in 1921 in Blenheim.