Carlos Fresco from London decided to take Monty to the peak of Pen y Fan in the Brecon Beacons, Wales, after seeing the 10-year-old dog's condition worsening.
The 57-year-old said Monty was weak but really enjoyed the trip as well as attention from wellwishers along the way.
Walking Monty's favourite trail for the last time
Fresco told Wales' local daily Brecon and Radnor Express that Monty loved hill walks so he took it on trips around the wonderful beacons.
"Although he was weak he enjoyed all the fuss and attention received by so many well wishers. People on the hills were so kind and equally so sad at his deteriorating condition. In fact total strangers asked if they could share in pushing Monty on his last journey - many total strangers shed a tear as we all love dearly our little four-legged friends.
“I would like very much to thank them all for their support, encouragement and genuine concern over Monty,” Fresco told the daily.
"I knew Monty was dying as his cancer had returned. He was diagnosed 18 months ago and responded very well to chemotherapy. But unfortunately his leukaemia returned eight weeks ago and he declined very rapidly," he explained.
Sadly, Monty died on 21 June and is now buried in Fresco's garden in London.
Rest in peace, Monty!