The Chelsea full-back has retired from international football after failing to make the England squad for the World Cup, and Hodgson has admitted to agonising over the decision
Cole announced his retirement from international football on Twitter after learning that he would not be included in Hodgson's squad for the finals in Brazil.
"Among many difficult decisions I've had to make for my squad, not selecting Ashley was one of the hardest," Hodgson told TheFA.com.
"He's been an incredible competitor for England, to amass over a century of caps is a truly staggering achievement and he deserves enormous credit for the desire and brilliance which has shone through over the years he has represented his country.
"There are few players who can be considered among the very best in the world, but Ashley in his prime was the best left back without question."
The news of Cole's omission was broken late on Sunday evening, and Hodgson said it was important to speak to the player before his squad his officially announced on Monday afternoon.
He added: "The most important factor was speaking to Ashley prior to the announcement on Monday, he deserved to hear it directly from me and he took the news with huge grace.
"In two years working with him he has shown nothing but relentless professionalism, and a great hunger to play for England. He is someone I have the utmost respect for and I wished him all the best, he in turn wished the team well this summer.
"Of course I must respect his decision to retire, he has been one of England's finest players, but I want to look to the future.
"It has been one of the hardest decisions of my career."
Goal understands that Hodgson will also leave out Manchester United midfielder Michael Carrick and Tottenham right-back Kyle Walker.