The Clermont Auvergne star has been recalled to the international set-up after a 16 month absence.
Halfpenny has made the number 15 jersey his own in recent years but Byrne insists he will fight tooth and nail for further honours.
“Leigh Halfpenny is playing well at the moment and has taken his chance well,” said Byrne.
“There are other younger players coming through as well, but I am just focused on trying to get in the match-day 23.
“It is one step at a time. But I would be disappointed if I am not involved against Ireland and I am not here to make up the numbers.
“It is just great being back in the squad.
“I have wondered whether the World Cup was the end for me, but it is just great to get another call-up.
“I was playing well in France and it is nice that has been recognised and I have been picked on form.
“It is strange being the oldest and I have been teased about that. But I don’t feel that old.
“Looking around you see a lot guys in their early 20s, but Matthew Rees, who is the same age as me, is still here which is reassuring.”
Warren Gatland was firmly in charge the last time Byrne was on the international stage but he has been succeeded by interim head coach Rob Howley.
The Clermont full-back has paid tribute to the former scrum-half and his backroom staff and reckons Wales can get back to winning ways following seven consecutive defeats.
“Rob Howley has changed roles well and the players know he is in charge,” said Byrne.
“There is going to be more pressure on him because Warren is such an important figure, but Rob has taken over the role in his stride.
“He has taken a step back in the on-the-field coaching. We have Mark Jones on board as backs coach now, along with Neil Jenkins, which is a great help so we still have plenty of people to work with.
“Things did not go well in the autumn.
“But there is a belief in this squad that, although we have a couple of injuries, we can still perform well in this tournament.”
