Why Abraham Lincoln was famous ?

 He had extraordinary strength and courage, in his resolve to go to war to prevent the nation from dividing.

He was a tenacious commander in chief during the Civil War.
He wrote and issued the Emancipation Proclamation, a set of 2 executive orders, which didn't immediately free any slaves because it only applied to territories not under Lincoln's control. The Emancipation Proclamation was the catalyst event, which led to the passage and ratification of the 13th Amendment, which did end slavery by legally abolishing it.

Through exemplification of his ambition and hard work, he demonstrated extraordinary success, from very humble beginnings, as well as, overcoming many failures.
 In his youth, he had less than 12 months in total education, and as a young man, he was entirely self taught in law. In 1836, he was licensed to practice law, become a very successful attorney with his own large law practice, prior to becoming President; yet, he had no apprenticeship training, and never attended college.

Lincoln set a legacy example with high character and integrity, when it came to leadership, which today, is still the "ideal example" we look for and compare to, in present day politicians.
He is also famous for his quotations. Politicians love to quote Abraham Lincoln because he is, considered America's wisest president.
Lincoln's unique style of leadership involved telling stories, which explained his actions and influenced others to follow his lead, and earned him the nick name, "Father Abraham".
He possessed qualities of kindness, compassion, which he combined with wisdom, and added to his skillful leadership; which, could almost, always win over an enemy, or soften them to his perspective.