After less than a year on the job, the president of Valley Forge Military Academy and College resigned suddenly on Friday, citing an unspecified “philosophical disagreement” with the chairman of the school’s board of trustees.

Walter T. Lord, who rose to the rank of major general during a 36-year career in the Army, said in a Facebook post Friday to Valley Forge alumni: “Since my arrival last April, I’ve had a philosophical disagreement with our board chairman and I’ve come to realize that a bridge between our perspectives was not reachable.”

Lord, 54, called it “the most difficult decision I’ve ever had to make.”

John English, the board chairman, said in a statement that the board "received Gen. Lord’s resignation letter during our board meeting earlier today, citing irreconcilable differences. The decision to resign was Walt’s, he resigned of his own accord.

“The board regretfully accepted his resignation and has committed to working with him to achieve an orderly transition, with both parties acting on what’s best for the institution we both love, honor, and respect,” English said.

Neither Lord nor English would elaborate on what led to the departure.

Lord’s resignation came exactly one year after the school announced his selection as president. Lord previously was a member of the board of trustees since 2013 and was chairman of the college oversight committee.

Lord, a South Philadelphia native, was a graduate of Valley Forge Military College and was the second alumnus to become president of the school.

Based in Radnor, the private institution has a preparatory boys’ school for grades six through 12 and a coed two-year college.

In his Facebook post, the retired two-star general said he would continue to support the school and urged other alumni to do the same.

Earlier Friday on his Twitter account, Lord posted a motivational quote: “Wisdom is knowing the right path to take ... Integrity is taking it.”

On Wednesday, he had posted another quote: “A bad manager can take a good staff and destroy it, causing the best employees to flee and the remainder to lose all motivation.”

The response on Facebook to the school’s announcement about the resignation was a mix of bewilderment, support for Lord, and hostility to the chairman.

“Three presidents in four years? As an alumnus, I am requesting, no INSISTING on a more detailed explanation other than irreconcilable differences,” one commenter wrote.