HOUSTON — Sully’s service didn’t end with the death of his master.

Former President George H.W. Bush’s service dog remained loyal, standing guard over the president’s casket Sunday and Monday.

Sully is being featured in his own tribute, seen Sunday lying in front of the 41st president’s flag-draped casket in Texas.

And the 2-year-old yellow Labrador retriever — named in honor of another hero — stood watch Monday as a joint services military honor guard carried the coffin during a departure ceremony to Washington, D.C., from Ellington Field in Houston.

Bush spokesman Jim McGrath posted a picture Sunday of Sully with the caption, “Mission complete. #Remembering41.”

As of Monday afternoon, the post had been retweeted 62,000 times and liked by more than 241,000 Twitter users.

Bush died Friday at his home in Houston at 94.

The former president came back to Washington for a final time Monday.

Sent off from Bush’s beloved Texas with a 21-gun salute, his casket was carried to Andrews Air Force Base outside the capital city aboard an aircraft that often serves as Air Force One.

Sully, the yellow Labrador retriever service dog of former President George H.W. Bush waits as joint services military honor guard carry the flag-draped casket of the remains of his master during a departure ceremony to Washington D. C at Ellington Field on December 3, 2018 in Houston, Texas. (Photo by David J. Phillip - Pool/Getty Images)

Sully waits as a joint services military honor guard carries the flag-draped casket during a departure ceremony to Washington D. C at Ellington Field on December 3, 2018 in Houston, Texas. (Photo by David J. Phillip – Pool/Getty Images)

He will be honored during several public and private events in Houston and Washington before his burial Thursday in Texas.

Bush received Sully in June from America’s VetDogs nonprofit organization. The president had a form of Parkinson’s disease, and Sully could open doors, pick up items and summon help.

 Former presidents George H.W. Bush, left, and Bill Clinton, right, pose with Sully during a visit earlier this year. (Evan F. Sisley/Office of George Bush via AP)

Former presidents George H.W. Bush, left, and Bill Clinton, right, pose with Sully during a visit earlier this year. (Evan F. Sisley/Office of George Bush via AP)

Sully will return later this week to America’s VetDogs in Smithtown, New York, according to the organization’s web site. After a brief holiday stay, he will join the Walter Reed National Military Medical Center’s Facility Dog Program, to help wounded soldiers in their physical and occupational therapy.

He was named after Chesley “Sully” Sullenberger III, the former pilot who landed US Airways Flight 1549 on the Hudson River in 2009, saving the lives of all 150 passengers and five crew in what came be be known as “The Miracle on the Hudson.”

“Sully the dog was raised and trained through the VetDogs prison puppy program, in which inmates raise future service dogs until the dog is about 15 months old,” according to the organization’s web site.

Contributing: Sun-Times staff