By Danielle DeSimone

It was an image that moved millions, both patriots and pet owners alike.

The photo, which was posted on Twitter shortly after the death of President George H.W. Bush, showed Sully, his yellow Labrador and service dog, lying beside the late president’s flag-draped casket at the US Capitol.

The caption read, simply, “Mission complete.”

However, nearly three months later, it turns out Sully’s mission was far from over.

Earlier today, Sully joined the ranks of Walter Reed National Military Medical Center’s facility dogs, which are tasked with reducing stress and improving the well-being of patients and staff at the hospital. Although they are trained as typical service dogs, these canines focus, instead, on providing emotional support to service members as they rest and recuperate from visible and invisible wounds at the hospital.

“I wouldn’t believe it if I didn’t see it with my own eyes, the transformative impact these dogs have on service members,” said John Miller, president and chief executive officer of America’s VetDogs, the nonprofit organization that trained Sully, and many other service dogs.

Surrounded by a crowd of service members, hospital staff, USO volunteers, and fellow facility dogs, Sully was appointed to the rank of petty officer, hospital corpsman second class. He traded his America’s VetDogs vest for his new military uniform vest, officially marking him a member of the Walter Reed Bethesda Facility Dog Program, and even received a personalized oath of enlistment:

“Do you affirm … or pant … as a hospital corpsman in the United States Navy that you will support, comfort and cure warriors and their families, active duty and retired? That you embrace our staff and bear unconditional love and solace, especially on busy days? That you take this obligation freely, without any promise of treats or tummy rubs and that you will faithfully discharge the duties to provide joy, love and nurturing for our soldiers, sailors, airmen, Marines and their families?”

At the end of the ceremony, Sully was given a quick paw shake before scurrying off to join his team of fellow facility dogs and carry on the legacy of his first owner. “This is exactly where Sully needs to be,” said Evan Sisley, the former personal aide and senior medic to Bush. “Continuing his mission.”

As Bush was a Navy veteran and a staunch supporter of the military, there was no question as to where Sully should go after the president’s passing. According to Sisley, “Sully came to the Bush family during a very difficult time … and he brought a light and levity” to Bush and the entire family in the final months of the former president’s life. Bush wanted Sully to continue to support as many service members and veterans as possible, and the decision was made for Sully to join the Walter Reed team.

Sully’s ceremony was hosted at the USO Warrior and Family Center in Bethesda, which was especially poignant, considering the location has served hundreds of thousands of wounded warriors and was originally dedicated to Prescott Bush, George H.W. Bush’s father.