He reached the South Pole on Friday, unassisted and unsupported, 47 days after setting off across Antarctica from Hercules Inlet.
Former British Army Gurkha officer Hayes, 45, is only the 15th person to have achieved the feat.
“I’m super-fit, and that really helps,” he told The Daily Telegraph by satellite phone.
He said the failure rate was high for attempts to reach each of the three extreme points on the Earth.
“Most explorers take several years to complete the challenge, but I am very lucky to have done it within 19 months,” Hayes said from the Amundsen-Scott base at the South Pole.
“It’s really difficult to do it any faster due to the sheer amount of physical and mental effort it requires, let alone preparation time and all the other resources.
“However, I must say that although it was an arduous trek it was fractionally easier than doing the North Pole.”
He reached the Everest summit on May 25, 2006, and the North Pole on April 25 this year.
Hayes is one of only 117 people to have walked the entire way to the South Pole in 96 years and one of only 57 people to reach the South Pole unassisted.
The corporate coach and motivational speaker is also one of only three people to reach both poles in one year.
He is the second Briton to have completed the “Three Poles” challenge.
His achievements have raised awareness and funding for the Children’s Hope Foundation and Friends of Cancer Patients charities.