James Philip Eagle was born in Maury County, Tennessee. His family moved to Arkansas early in his life and he was educated in the public schools.
Eagle was appointed deputy sheriff of Prairie County, Arkansas in 1859, a position he held until the start of the American Civil War. Eagle enlisted in the Confederate States Army and rose to the rank of Colonel. He served with the 5th Arkansas Infantry and the 2nd Arkansas Mounted Rifles. He campaigned with the Army of Tennessee and fought in most of that army's campaigns from the initial battles in Kentucky all the way to the Battle of Nashville. Eagle was wounded during the Atlanta campaign.
At the conclusion of the war Eagle attended Mississippi College for less than one year but was forced to withdraw due to illness.
From 1873 to 1878 he served as a member of the Arkansas House of Representatives. In 1875 Eagle served as speaker of the house. From 1880 to 1904 he served as president of the Baptist State Convention.
In 1888 Eagle was elected Governor of Arkansas. In 1890 he was reelected for a second term. The Eagle administration concerned itself with attracting immigration and support for education. Eagle was sympathetic to women's suffrage and once welcomed Susan B. Anthony to the state though he did not provide active political support.
Eagle was elected as president of the Southern Baptist Convention in 1902 and was reelected to that position twice more. He continued to be active in the Baptist church. Eagle served on the state capitol commission but was fired by Governor Jeff Davis for allegedly campaigning for an opponent of Davis. Davis was opposed to the construction of the new capitol building.
James P. Eagle died in Little Rock, Arkansas of heart failure. Eagle is buried at the historic Mount Holly Cemetery in Little Rock.