The 10-minute speech mentioned the president just a handful of times and was much kinder to the White House than many of her Republican colleagues. Instead of focusing on Obama, Ernst laid out a GOP agenda that will face stiff opposition in Congress, even with Republican control of both the House and Senate.
Ernst talked about GOP priorities like approving the Keystone XL pipeline and repealing the Affordable Care Act, two partisan issues that would be vetoed by the president.
"That's why the new Republican majority you elected started by reforming Congress to make it function again," she said. "And now, we're working hard to pass the kind of serious job-creation ideas you deserve."
Read MoreState of the Union: 'Shadow of crisis has passed'
Republican Kentukcy Sen. Rand Paul took to YouTube to deliver his own personal response to the president.
"America is adrift, something is clearly wrong," the portential 2016 presidential candidate said. "America needs many things but what America desperatly needs is new leadership."
But many in the GOP had much harsher critiques of the president's speech.
Read MoreStocks that may get a State of the Union boost
"True to form, the president in his State of the Union speech is more interested in politics than in leadership," 2012 Republican presidential nominee and possible 2016 candidate Mitt Romney said in a post on Facebook.