Miller began a business career by clerking in stores and working as a sewing machine salesman.

He served until the end of the Civil War, and turned down an Army commission despite having performed well on the competitive examination.

[8][9][10][11][12] In 1919 Miller left Galena-Signal and became chairman of the board of the Home Oil Refining Company of Texas.

[15][16] Miller also served in appointive offices, including member of the board of trustees of the Pennsylvania Soldiers' and Sailors' Home.

He operated a night school at his own expense to enable Franklin residents to finish high school or receive training in business skills, and also made substantial donations to the local Baptist church, of which he was a founder, the YMCA, and the local library.

[19] In 1880 Miller returned to military service as ordnance officer of the Pennsylvania National Guard's 2nd Brigade with the rank of major, where he served under commander James A. Beaver.

[24] To recognize Miller's contributions to business and industry, in 1901 the government of France awarded him the Legion of Honor (Chevalier).