Lt. Gen. Jay Silveria told cadets to line up and pull out their phones to remember his message, and he forcefully denounced racism and intolerance.
"If you're outraged by those words, then you're in the right place. That kind of behavior has no place at the Prep School," Silveria said.
The speech was posted on Air Force Academy's Facebook page and quickly went viral.
The Air Force launched an internal investigation to find the culprit.
But on Tuesday, Air Force Academy officials said that one of the black cadet candidates actually wrote the racist messages.
"We can confirm that one of the cadet candidates who was allegedly targeted by racist remarks written outside their dorm room was actually responsible for the act," the Academy said in a written statement. "The individual admitted responsibility and this was validated by the investigation."
The vandalism was written in black marker and said "Go home" with the N-word, according to CNN affiliate KRDO
Lt. Col. Allen Herritage, director of public affairs with the Academy, said that the cadet responsible admitted his guilt when confronted. The individual has "received administrative punishment" and is no longer at the preparatory school, Herritage said.
The four other students that were the target of the vandalism are still at the Prep School, which is on the same campus in Colorado Springs, Colorado, as the Air Force Academy. The Prep School helps ready about 240 cadets each year to enter the academy.
'This is our institution'
Silveria, the Academy's superintendent, made clear in his speech in September that there would be no tolerance for racist rhetoric at the Academy.
"If you can't treat someone from another gender, whether that's a man or a woman, with dignity and respect, then you need to get out," he said. "If you demean someone in any way, then you need to get out. And if you can't treat someone from another race or different color skin with dignity and respect, then you need to get out."
"This is our institution, and no one can take away our values," Silveria added. "No one can write on a board and question our values. No one can take that away from us."
Although the hateful graffiti was revealed to be a hoax, the Air Force Academy affirmed that same message of dignity respect in a statement on Tuesday.
"Racism has no place at the Academy, in any shape or form. We will continue to create a climate of dignity and respect for all, encourage ideas that do so, and hold those who fail to uphold these standards accountable."
Silveria said in a statement on Tuesday that his speech remained relevant despite the investigation's outcome.
"Regardless of the circumstances under which those words were written, they were written, and that deserved to be addressed," he said. "You can never overemphasize the need for a culture of dignity and respect and those who don't understand those concepts aren't welcome here."