Pearce, who also led Great Britain at the 2012 Olympics, has been the subject of criticism from some quarters after a disappointing summer European Championship where his team lost all three of their group games.
His contract runs out at the end of June and he is due to discuss his future with the FA amid speculation he is set to leave.
But Horne has praised Pearce, as he told Sky Sports News: "Stuart has brought to his country and to the U21 side a huge amount of passionate leadership.
"Do not forget he has qualified for four tournaments in a row, which is unprecedented, and he qualified top of the group last time.
"Stuart has brought a huge amount of professionalism to the FA, not only with the U21s but also with his spell with the Olympic team."