Blair has played 39 tests for the Kiwis, since making his debut in 2006. The 30-year-old was part of the 2008 World Cup winning side and was the starting prop in the 2010 Four Nations final victory.
The Whangarei-born Blair is one of a handful of Kiwis with five test wins over the Kangaroos, including the three-peat between November 2014 and May 2015.
Kidwell confirmed Blair's appointment this morning.
"There is one guy that sticks out. I had to look at respect of the peers, staff, what they had done in the game and I brought all those factors in there to decide who was going to be the leader taken into the World Cup," Kidwell said.
"I also looked at how [he] prepares off the field [and] leads on the field as well. It was a really important part of my decision."
The appointment will be for the duration of the tournament.
Kidwell also confirmed there will be significant changes to the off-field protocols around the team for the World Cup, starting in October.
The Herald on Sunday understands an alcohol ban for periods of the tournament is being considered by the Kiwis' management group. There is also a possibility of post-match activities being confined to a team room at the Kiwis' hotel.
There could also be a return to the policy between 2010 and 2012, when the Kiwis were generally not allowed to leave the hotel after a defeat.
Bromwich and Kiwis team-mate Kevin Proctor were banned after being caught on CCTV allegedly using cocaine following the Anzac test loss to Australia.
"There will be changes to the post-match protocol," Kidwell told the Herald on Sunday.
"My trust has been broken and we are changing our protocols for after the game, in line with the leadership group as well. I trusted these guys and it is something that has never happened before in one-off tests. It's something that we are looking at."
Kidwell didn't want to go into specifics, but admitted all aspects have been examined.
"The changes will be kept private. We need our players input as well. That will definitely be in place before we come in for the World Cup."
He admitted the balance between allowing players to let off steam after a match and not compromising the high performance values of the team was delicate.
"That's the balancing act," he said. Kidwell denied allegations made in the Herald last week that there were also alcohol-related incidents on the Kiwis' Four Nations tour last year, involving at least one high profile player.
"I don't know where you are getting your information," he said.
"Tours are like big families. There are always little incidents that happen here and there but nothing major."
