Trustees say the academy is no longer viable.
They cited several reasons, saying that the rising cost of the boarding school is now less affordable for many families, leading to a sharp drop in enrollment.
School officials also say changes in Pennsylvania law increased the Academy's liability exposure, and they were hit with steep insurance premium increases.
However, it is important to note that this does not affect Valley Forge Military College, which shares a campus with the academy in Wayne, Delaware County.
Interim head of school, Aaron Barkley, told Action News, "Basically, our lifeblood is tuition. So, when our enrollment goes down, that does affect our ability to sustain and to operate."
Barkley said there are about 90 cadets currently enrolled at the academy. When he started working at the boarding school in 2011, he said there were about 300 cadets.
Barkley called this a "difficult time" for the dozens of students and the 20 people employed by the school.
"Obviously, it's disappointing for all of us, especially our underclassmen," Barkley said. "We had some students expecting to graduate from Valley Forge Military Academy, and that's not going to be a reality."
For almost 100 years, the private school has educated young men in grades 7 through 12.
In the '90s, Maryland Governor Wes Moore called the school home. He released this statement about the closure on Monday:
"I walked onto the Valley Forge campus as a twelve-year-old boy with a complicated past and a questionable future. I walked away as a graduate and an Army officer with a love of our country and a commitment to preserve its future. My experience at Valley Forge is exemplary of the pivotal role it has played in building character, empathy, focus, and drive within so many of the young people it has served over 97 years. I am proud and grateful to be counted among the long line of Gray. Courage, honor, conquer."
Another notable former student at the school is Larry Fitzgerald. The former NFL player attended the academy in 2001.
Philadelphia native Kareem Rosser got a scholarship to play on the academy's polo team when he was in 8th grade.
Now serving as the executive vice president of the Philadelphia nonprofit, Work to Ride, Rosser said he is disappointed to hear the academy that changed his life is closing its doors. "I showed up as a lost boy from inner city Philly... I credit Valley Forge, really, with shaping me into the person and leader that I am today," he said.
Action News also spoke with Andrew Tuturice, who is currently in his senior year at the academy.
"Valley Forge is one big family, if you will," he said.
The Ambler native said he enrolled in Valley Forge Military Academy as a freshman, hoping to better himself. He will now be part of the school's final graduating class.
"I'm really glad I'll be able to keep with Valley Forge history and traditions and be a Valley Forge alumni," he said.