The Tennessean is the third ranking Republican in the Senate and the first member of the leadership to express his support for Sotomayor's nomination.
"Even though Judge Sotomayor's political and judicial philosophy may be different than mine, especially regarding Second Amendments rights, I will vote to confirm her because she is well qualified by experience, temperament, character and intellect to serve," Alexander said in a speech on the Senate floor, according to the Associated Press.
In his comments, Alexander echoed sentiments made by another Republican senator who supports Sotomayor, Lindsey Graham, arguing that senators should show some deference to the president.
"It is my hope that my vote now not only will help to confirm a well-qualified nominee but will help to return the Senate to the practice, only recently lost, of inquiring diligently into qualifications of a nominee and then accepting that elections have consequences, one of which is to confer upon the president the constitutional right to nominate justices," Alexander said.
During Sotomayor's confirmation hearings, Graham said simply, "elections matter."
Alexander is the sixth Republican to announce support for Sotomayor's confirmation.