Harris, is in his second term representing the Eastern Shore and portions of Baltimore's northern suburbs. The announcement comes weeks after Maryland Democrat Barbara A. Mikulski was named as the chairwoman of the Senate Appropriations Committee.
Harris replaces Jo Ann Emerson, a Missouri Republican who retired.
"His commitment to responsible federal spending will serve the committee well as we navigate the uncharted waters of this precarious fiscal situation," House Appropriations Committee Hal Rogers, a Kentucky Republican, said in a statement.
Harris represents a safe GOP district after the state's congressional redistricting in 2011. The new maps helped Democrats unseat incumbent Republican Roscoe G. Bartlett in Western Maryland, making Harris the sole Republican member of the state's congressional delegation.
"I look forward to joining Chairman Rogers to control spending and put our nation back on a path toward fiscal responsibility," Harris said in a statement. "It's time we deal with America's fiscal challenges instead of continuing to pass them onto our kids and grandkids."
The appointment means Maryland unexpectedly went from having no appropriators in its delegation to two over the course of a few weeks. The spending committees don't have the sway they once did. Congress is more focused on cutting than spending and pet projects known as earmarks have been banned.
But the lawmakers who serve on the committees will ultimately decide which programs are cut and which are spared.
Harris, a conservative, will serve on the following subcommittees: Commerce, Justice, Science, and Related Agencies; Labor, Health and Human Services, Education, and Related Agencies; and Legislative Branch.