Which american writer and humanist composed and ceaselessly reconsidered an accumulation of ballads called leaves of grass?

It was Walt Whitman.

Explanation:

Walt Whitman was an American poet who lived from 1819 to 1892. His major work, "Leaves of Grass", was published in 1855. He is, to this day, considered one of the greatest writers in America, often called the father of free verse.

In famous poems such as "I Hear America Singing" and "O Captain! My Captain!", Whitman presents his patriotism and seems to see America as a country of freedom and possibilities. Of course, there are critics who claim that Whitman's nationalist views were not in favor of Native-Americans and African-Americans, among other groups. Still, his approach on democracy is still respected to this day.

During the civil war int he U.S., he worked in hospitals are cared for the wounded. Whitman died at the age of 72 when his health greatly declined after a stroke.