Who was the leader of the fireside poets?

Answer:

The "Fireside Poets" was a common name for the American poets whose books sold well in the 1860's and later. The "Fireside Poets" never particularly thought of themselves as a group; they all shared a populist approach, but the name was applied to them - it wasn't one they chose for themselves.

There is no definitive agreement on who the Fireside Poets were. Lowell, Longfellow, Whittier, Bryant and Holmes are nearly always included - but some critics add Sidney Lanier, even Melville - while others don't.

Since the Fireside Poets were never really a group - except in popular imagination - they never really had a leader.