to take the lead; to stand at the front of a group and lead or take initiative.
新しいプロジェクトでは彼女が先頭に立って進めることになった。
She was chosen to take the lead on the new project.
困難な時に先頭に立つ人が必要だ。
A person who takes the lead is needed in difficult times.
行列の先頭に立って旗を振った。
I stood at the head of the procession and waved the flag.
部長が率先して先頭に立つと、部下もやる気になる。
When the manager takes the lead, the subordinates also become motivated.