Final answer:
Walt Whitman became famous with the publication of the first edition of Leaves of Grass in 1855.
Step-by-step explanation:
Walt Whitman first became famous with the publication of the first edition of Leaves of Grass in 1855. This collection of twelve poems showcased Whitman's love for wordplay and common images, and it established him as a poet who celebrated the ordinary. Over the years, Whitman expanded the collection, ultimately including more than 400 poems. His ability to connect the great and the common through language made his works enduring.