Prior to the Civil War, Alden operated the "underground railroad" in Dearborn County, Indiana, risking his life and liberty to shepherd African Americans from slavery in the south, to freedom in the north.
When the war broke out, Alden enlisted in the Union Army as a Captain on August 9, 1861. He raised a company of men, mostly family, friends and neighbors from around the Dearborn county community. He took command and mustered them into the Union Army at Indianapolis as Co K, 26th Indiana Volunteer Infantry on Aug 31, 1861 .
Major Engagements in which Alden participated:
Union Army's Western Campaign
* Battle of Prairie Grove, Ark Dec 7, 1862.
* Siege of Vicksburg, Miss Jun 11-Jul 4, 1863. (Wounded)
Rio Grande Expedition
* Battle of Brownsville, Tex Nov 2-6, 1863
Re-Enlisted Aug 30, 1864
Siege of Mobile, Alabama
* Battle of Fort Blakeley, Ala Apr 2-9, 1865
Promoted to Major 15 Apr 1865
Breveted Lieutenant Colonel 10 October 1865
Mustered out of service Jan 15, 1866

Source:
Report of the Adjutant General of Indiana
US Library of Congress, Indiana -- Militia; United States -- History Civil War, 1861-1865 Regimental histories Indiana; Indiana -- History Civil War, 1861-1865

Alden died on 29 February 1888 at Melvern, Osage Co., Kansas, at age 69. An excerpt from a memoriam written by an unnamed comrade from Scranton,Kansas on March 5, 1888 reads as follows:
"Major Jumper has obeyed the bugle call that is fast gathering the volunteers who wore the blue to the eternal camping ground, and whose reveille will soon sound for the last comrade on this side of the river. And it is well. A sorrowing family he has left - an affectionate wife, children whose love for him cannot be measured by words, and friends and neighbors who sadly realize their loss. But our grief is in part compensated. He could not see here - almost blind for years - but he sees there! Here he recognized friends by voice; there his eye kindles with the luster of youth as he greets the dear ones gone before, and strikes hands with the comrades who lay by his side in the trenches, kept step with him on the weary night march, and slept with him under the winter stars in the damp swamp or on the bleak hillside. Major Jumper was the deadly foe of shams. He believed in calling things by their proper names. This fact is shown by the title preceding his name. Many men with a colonel's commission would have enjoyed no less a title than General, but he desired to be known as we knew him and called him Major.... In this country he had a few if any equals in debate. Fearless and confident he stood before the people and the man who measured swords with him upon the platform of stage found a foe man worthy of his steel...".
He was buried in in the Melvern Cemetery at Melvern, Kansas.