Speed was born in Nelson County, Kentucky, and was a prominent attorney in Indiana with Benjamin Harrison. In 1889, he moved to Winfield, Kansas, and following the Run of '89 he established a law practice in Guthrie, Oklahoma Territory. His experience with the Cherokee Commission led now President Benjamin Harrison to appoint him United States Attorney for the territory (1890–1894). He served again for a short time in 1900 as the last territorial US Attorney before it was divided into districts. As US Attorney he prosecuted many of the outlaws running rampant in the territory and the land fraud cases that troubled the land openings.