Near the end, the king says that he had not accomplished much and that he would be forgotten. At one point earlier he referred to a minor tomb that was being prepared for some nobleman. Due to the sudden and unexpected death of the king, it was in that tomb that he was placed.
He was not an important king in any way. After his passing, his name was expunged from all of the public monuments and carvings, as the episode of his father's religious rebellion that affected Tut in his childhood made him and his family line taboo. Despite his insignificance (and in fact because of it) he became the best known of all the kings of Egypt. This is because his tomb, which did not have a grand entrance but rather a series of steps leading down into the ground, was quickly filled in over time and was forgotten.
Although grave robbers had entered not long after his death and made of with many things, the robbery was discovered and the majority of the looted items was tossed into the tomb and hastily resealed and buried. Because of this, hundreds of funerary objects along with a great many of his possessions (even including disassembled chariots and beds) survived to be discovered in the 1920s. Further, as the thieves had not had time to break into the section of the tomb containing the mummy, everything associated with it survived. A half century later, many of these objects, including his famous lifelike gold mask made several world tours, being displayed in many museums in America and Europe.