He also served as a member of the Pennsylvania State Senate for the 20th district from 1863 to 1886 including as speaker in 1871.

He served as a captain of the Clearfield Guards in 1854 and became a prominent member of the Peace Democrats from Pennsylvania during the U.S. Civil War.

While in the State Senate, Wallace was member of a commission charged with drafting amendments to the 1874 Pennsylvania Constitution.

[2] In 1875, Wallace was elected as a Democrat by the Pennsylvania General Assembly to the United States Senate.

He worked as vice president of the Texas and Pacific Railroad, president of the Beech Creek Railroad, director of the Clearfield Cemetery Association and part owner of the Wallacetown Brick Company.