FORT BRAGG, N.C. — Sergeant Bowe Bergdahl was dishonorably discharged from the Army by a military judge on Friday, but received no prison time for desertion and endangering troops, ending a drama that began more than eight years ago in war-torn Afghanistan.

At the sentencing hearing, the military judge, Colonel Jeffery R. Nance of the Army, also reduced Bergdahl’s rank to private and required him to forfeit $1,000 a month of his pay for 10 months.

The sentencing took only a few minutes: The judge entered the courtroom, read the verdict, and left shortly after. Nance did not explain the reasoning for the sentence that he imposed.

About 90 minutes after the hearing, President Trump posted a Twitter message denouncing the sentence: ‘‘The decision on Sergeant Bergdahl is a complete and total disgrace to our country and to our military.’’

The sentence will be reviewed by General Robert B. Abrams, who convened the court-martial, and has the power to lessen the punishment. If the final sentence still includes a punitive discharge, it will then automatically be reviewed by the US Army Court of Criminal Appeals.

Politics dogged the case from the start. The Obama administration embraced Bergdahl — the national security adviser, Susan E. Rice, said that he had served with “honor and distinction — a portrayal that angered congressional Republicans.

Then, last year, Trump made Bergdahl a staple of this campaign speeches, denouncing him as a “dirty rotten traitor’’ and calling for him to be executed.

Trump, who is beginning a trip to Asia, quickly criticized the verdict. “The decision on Sergeant Bergdahl is a complete and total disgrace to our Country and our Military,’’ he said on Twitter.

Bergdahl was 23 and a private first class when he walked off his base in eastern Afghanistan in June 2009.

Army investigators would later characterize his departure as a delusional effort to hike to a larger base and cause enough of a stir that he would get an audience with a senior officer to report what he felt were problems in his unit.

But the soldier, who is now 31, was captured by the Taliban within hours, and would spend five years as a prisoner, his treatment worsening after every attempt he made to escape.

He was beaten with copper cables, and held in isolation in a small metal cage. He suffered dysentery for most of his captivity, and cleaned feces off his hands with his own urine.

The military searched for him, and several troops were wounded during search missions. One of them, Sergeant 1st Class Mark Allen, was shot through the head and lost the ability to walk, talk or take care of himself, and now has minimal consciousness.

His wife, Shannon, testified that he is not even able to hold hands with her any more. On a separate rescue mission, Senior Chief Petty Officer Jimmy Hatch, a Navy SEAL, suffered a leg wound that would require 18 surgical procedures and end his long career in special operations.

Bergdahl, who was promoted while in captivity, was freed in 2014 when the Obama administration exchanged five Taliban detainees at Guantánamo Bay for him, setting off a political furor that still reverberates. Congressional Republicans were angered by the release of Taliban prisoners and by the way the Obama administration portrayed the sergeant.

Army investigators quickly dismissed claims that troops had died searching for Bergdahl, or that he had intended to defect to the Taliban.

They suggested that he could be prosecuted for desertion and for some lesser crimes.

But in March 2015, the Army raised the stakes, accusing him not only of desertion but also of misbehavior before the enemy, an ancient but rarely charged crime punishable by up to life in prison. In this case, the misbehavior was endangering the troops who were sent to search for him.

Even so, the sergeant’s defense seemed to have some momentum.

The Army’s chief investigator on the case testified at Bergdahl’s preliminary hearing that he did not believe any jail time was warranted, and the preliminary hearing officer suggested that the whole episode might have been avoided “had concerns about Sergeant Bergdahl’s mental health been properly followed up.’’

But the four-star general in charge of the case at Fort Bragg ordered that Bergdahl face a court-martial on both charges.

Once Trump was inaugurated, Bergdahl’s defense team, led by Eugene R. Fidell, who teaches military justice at Yale Law School, demanded that the case be dismissed.

Nance labeled Trump’s comments about Bergdahl “disturbing’’ but declined to throw out the case.

Then, last month, Trump seemed to endorse his earlier sentiments about Bergdahl, saying, “I think people have heard my comments in the past.’’

During the sentencing hearing, Bergdahl took the stand and apologized for his actions, saying that he never intended for anyone to get hurt, and that he grieved “for those who have suffered, and their families.’’

The lead Army prosecutor, Major Justin Oshana, drew a comparison between Bergdahl and those who were hurt through his actions. “It wasn’t a mistake,’’ Oshana said of the sergeant’s decision to walk off his base. “It was a crime.’’