William Doolin was born on a farm in Johnson County, Arkansas, in 1858. Doolin moved to Logan County, Oklahoma in 1881 where he became a cowboy. He worked for a series of ranchers and developed a reputation as a trustworthy and a capable worker.

Doolin was apparently a law-abiding citizen until he attended a party at Coffeyville. Kansas had banned the consumption of alcohol and when the law turned up to confiscate the beer Doolin opened fire wounding two officers. Doolin fled from the scene of the shooting and soon afterwards joined the gang led by Bob Dalton. Other members in the gang included Emmett Dalton, William Dalton, Grattan Dalton, George Newcomb, Charlie Bryant, Bill Powers, Charlie Pierce, Dick Broadwell and William McElhanie. Over the next 18 months the Dalton gang robbed banks and trains throughout Oklahoma.

On 5th October, 1892, the gang planned to rob a bank at Coffeyville but Doolin's horse went lame and he did not take part in the crime. It was a lucky let off for Doolin as three of the gang were killed during a fierce gunfight that took place during the robbery. This included Bob Dalton, Grattan Dalton, Bill Powers and Dick Broadwell.

Doolin now formed his own gang that included William Dalton and robbed a train at Caney (14th October, 1892) and a bank at Spearville (1st November, 1892).

After marrying Edith Ellsworth on 4th March, 1893, Doolin robbed a train on 10th June, 1893. During the raid Chris Madsen shot Doolin in the leg. He recovered from his wounds and on 29th January, 1894, Doolin robbed a bank at Pawnee. This was followed by further robberies at Woodward, Oklahoma (13th March, 1894) and Southwest City, Missouri (10th May, 1894). During the Southwest City raid, J. C. Seaborn, a former state senator was murdered.

On 3rd April, 1895 the Doolin gang robbed a train at Dover, Oklahoma. He then tried to live a quiet life in New Mexico but returned to criminal activity the following year. Bill Tilghman arrested Doolin at Eureka Springs, Arkansas on 15th January, 1896. He was taken to Guthrie but managed to escape from jail on 5th July, 1896.

William Doolin was killed during a shootout with Heck Thomas, Bill Dunn and Bee Dunn on 25th August, 1896.