Joseph W. Fisher was born in Northumberland County, Pennsylvania, and was educated in the local schools.

Licensed as an attorney, he established a profitable legal practice serving the Northumberland County region.

He was promoted to the rank of colonel on July 1, 1862, after Col. Seneca G. Simmons was killed in action at the Battle of Glendale.

The Reserves were removed from the field to recover from hard service in 1862, and Fisher commanded the brigade in the XXII Corps, Department of Washington.

Col. Joshua Lawrence Chamberlain reported that his 20th Maine Infantry and Fisher's Brigade were sent to occupy Big Round Top late on July 2, 1863.

Chamberlain claimed that Fisher was unwilling to advance against unknown odds and that his unit, battle worn as it was, had to lead the way.