The Minnesota senator will fly to Texas on Monday and appear with the former vice president to deliver the endorsement in person.
Her exit from the race comes on the heels of Pete Buttigieg's and just ahead of her home state of Minnesota voting on Tuesday.
In recent weeks after her surprise third-place finish in New Hampshire, Klobuchar gained a blast of momentum — but the costs of continuing, and her lack of political relationships with voters beyond the white Midwest and northeastern states where she performed well, proved to be too much. She performed poorly in the significantly more diverse states of Nevada and South Carolina.
From the beginning, Klobuchar had positioned herself as the center-left alternative to more left-leaning populists like Sens. Elizabeth Warren and Bernie Sanders. Focused in particular on prescription drug prices and mental health coverage, Klobuchar proposed more modest plans on liberal policy priorities with an eye toward cost. She also emphasized her own electoral success in Minnesota, an increasingly competitive state that President Donald Trump hopes to win this year.
Klobuchar's candidacy never quite took off in the way of Buttigieg's campaign — something she was plainly frustrated by, arguing there was a double standard when it came to his inexperience and gender. But in polling, she also struggled with voters who weren't suburban white Midwesterners, something that became a major issue as the campaign continued.
Positioned in a visible Senate seat in a key state, Klobuchar, 59, remains positioned for a vice presidential nomination or even a second presidential run in four years if Democrats do not take back the White House this year.