The major influential or two famous personalities in transcendentalist movement are Ralph Waldo Emerson and Henry David Thoreau. Ralph Waldo Emerson was an American essayist, lecturer, philosopher, and poet who led the transcendentalist movement of the mid-19th century. Henry David Thoreau was an American essayist, poet, philosopher, abolitionist, naturalist, tax resister, development critic, surveyor, and historian.