Gabbard, a military veteran and former Democratic congresswoman from Hawaii, was confirmed by a 52-48 vote, with Democrats opposed in the sharply divided Senate where Republicans hold a slim majority.
The only "no' vote from a Republican came from Sen. Mitch McConnell, R-Ky.
"In my assessment, Tulsi Gabbard failed to demonstrate that she is prepared to assume this tremendous national trust," McConnell wrote in a statement.
"The nation should not have to worry that the intelligence assessments the President receives are tainted by a Director of National Intelligence with a history of alarming lapses in judgment.