David McLaren Kerr, who died at the age of 90, had lived at The Bupa Plas Cae Crwn care home in Newtown.
His funeral was held at Emstrey Crematorium in Shrewsbury on Tuesday afternoon.
Serving and former servicemen and women lined the entrance to the crematorium, giving him an emotionally charged guard of honour.
Taking to social media - the platform by which Newtown-based funeral directors Leach & Son made a nationwide appeal for mourners - those who could not attend showed their respect for those who did and for Mr Kerr.
Becky Fraser wrote on Facebook: "So glad his last voyage was attended by fellow service men. Yes, no one knew him but they had the respect to ensure his funeral was not a lonesome one. He wanted someone to do a reading and it was by someone who didn't know him as he has no family alive to do so.
"Much respect to the veterans of this countries and the current servicemen and woman."
Aaron Elvis Crofts added: "David Kerr had been in one of the elite British forces. This man was a real life. LEGEND."
And Dawn Woodward said: "So happy to hear this! I was so hoping his service would be well attended and even though I couldn't go myself, I feel better for knowing there are good folks around who did manage to show their respects."
Sheila Barton added: "That's wonderful, he had no family. It goes to show with the people who attended, he was never forgotten, he can now rest in peace."
And Carol Davies wrote: "Truly amazing. Well done Shrewsbury folk and others who travelled from afar."
Her sentiments were echoed by Jill Snape: "Very, very heartwarming!! Wonderful send off for him."
Jessicah Kendrick wrote: "That’s really lovely but I can’t help but wonder how many visitors he had in the days/weeks/months leading up to his death. Perhaps we could all make an effort to visit retirement homes or befriend elderly people who are alone?"
A memorial service will be held at Plas Cae Crwn in the coming weeks and Mr Kerr's ashes will be laid alongside the ashes of his late wife Nancy, according to his wishes. The couple also had a daughter Maryanne.