Poland attained the rank of brigadier general and was most notable for his command of the 17th Infantry Regiment and 2nd Division, First Army Corps.

[5] Poland took part in the Northern Virginia campaign of August to September, 1862, including the Second Battle of Bull Run.

[5] On December 13, 1862, Poland was promoted to major by brevet to recognize his heroism and superior service at Antietam, Shepardstown, and Fredericksburg.

[5] At the July 1863 Battle of Gettysburg, Poland served as aide-de-camp to the III Corps commander, Daniel Sickles.

[5] After the Civil War ended, Poland was assigned to the United States Military Academy faculty.

[5] After a leave of absence during late 1872, Poland served on frontier duty at Headquarters, Department of Dakota from January to June 1873.

[5] After another extended leave, in November 1881 he joined the faculty of the new School of Application of Infantry and Cavalry at Fort Leavenworth.

[5] The institution was subsequently renamed the Infantry and Cavalry School, and was the predecessor of the United States Army Command and General Staff College.

[5] Poland performed frontier duty with his regiment at Fort Bridger, Wyoming Territory from October 1886 to May 4, 1887.

[5] In 1891, he commanded an ad hoc battalion of the 21st Infantry at the Rosebud Agency in South Dakota during the Ghost Dance War.

[5] In April 1898, Poland was assigned to command first the 2nd Provisional Brigade and then the 2nd Independent Division, units that were organized at the start of the Spanish–American War.