The KPD detailed in a Monday news release that department authorities first responded to the officer-involved shooting around 3:15 p.m. local time.
According to a preliminary investigation, there was a "male subject who was possibly armed in the school. Upon approach of the subject, shots were fired."
Authorities confirmed that one male was pronounced dead at the scene and one KPD officer was transported to nearby UT Medical Center with non-life-threatening injuries.
One man has been "detained for further investigation." The release did explicitly identify the detained individual as a suspect.
The ongoing investigation is being handled by the Tennessee Bureau of Investigation.
Facebook Live footage recorded by user Phylicia Tate shows authorities entering the school building shortly after the incident.
Bob Thomas, superintendent of Knox County Schools, confirmed that those "who were not involved in the incident have been released to their families."
During a Monday news conference on education, Tennessee Governor Bill Lee briefly spoke about the school shooting.
"I've just been informed about that, just recently," he said, noting that details remain forthcoming from law enforcement. "I just wanted to make reference to that and ask for you all to ... pray for that situation."
Community concerns about gun violence have been growing following a string of shootings this year that have claimed the lives of at least four children, all former students of Austin-East High School.
Most recently, 15-year-old Jamarion Gillette died from gunshot wounds on March 9.