More than 97% of the clubs voted for governance change put forward by the WRU at an extraordinary general meeting in Port Talbot.
The changes will now set to be completed by the end of 2023.
"The important thing is it's a positive starting point," said Walker.
The changes will now allow the doubling of independent members (INEDs) on the board from three to six.
This includes the introduction of an independent WRU chair for the first time, alongside the PRB chair in addition to four separate independent members.
The rise of independent members means the number of elected national or district members will be halved from eight to four.
"I said before today's meeting it was impossible to overhype an event such as the one we had today," added Walker.
"We simply had to vote for change otherwise the future of Welsh rugby was in doubt.
"The feelings and emotions at the moment are one of relief rather than jubilation or joy; I suspect that will come. But also we know this is not the end of it, this is where the hard work starts.
"We have to repay the faith the clubs have shown in us today. 97% of clubs voted for change and the proposal that was on the table and we are delighted about that.
"But we recognise now we have got to back up the words with actions."
The WRU will now attempt to redress the gender imbalance, with an ambition that at least five of the 12 board members are women, including one of the top two jobs - the chief executive or chair.
Catherine Read, one of the three independent non-exec directors alongside PRB chair Malcolm Wall and Henry Engelhardt, is currently the only female member of the 12-strong board.
"We have said it's an aspiration to have five women on the board," added Walker.
"We have engaged a head-hunter in that search and as a man I would not be arrogant enough to suggest we won't have enough good women putting themselves forward so we are very hopeful.
"It maybe a journey and we may get to three women, then four and five and then six or seven.
"The important things is the organisation is open to change and wants to be welcoming to people of all persuasions, both genders, social class, religion and everything. That is what we want Welsh rugby to be.
"It's taken too long and the warning signs have been there for quite some time and they have been ignored.
"We had a real wake-up call and responded and the membership has voted emphatically for change. Now it's our job to make sure that change is enacted."
Former Professional Rugby Board (PRB) chair Amanda Blanc stepped down from that role and the WRU Board in November 2021 after saying she experienced misogyny at the organisation.
Aviva Group CEO Blanc has said she was not listened to at the WRU.
When asked whether somebody of that stature could return, Walker replied: "The lines of communication have always been open.
"It is not my decision to make for her as either a potential chair and CEO, but I'm sure that thought will have crossed many people's minds."
The latest board proposals came in the wake of a catalogue of damaging allegations that saw chief executive Steve Phillips resign.
His interim replacement, Walker, was forced to appear before a Senedd hearing following a BBC Wales Investigates programme that provided allegations of sexism and misogyny within the governing body.
The WRU is still being investigated by an independent taskforce led by former judge Dame Anne Rafferty concerning the culture within the organisation.
When asked whether he thought Welsh rugby is currently institutionally sexist and misogynistic, Walker added: "I'm not going to make a judgement on that.
"We've got a review which is underway and I'm sure Dame Anne Rafferty and the panel will come to a view on that.
"If that's the view we have to accept it and move forward. It's not for me to say.
"We are not the only organisation in this country at the moment who are going through these things.
"If it is identified that we have issues in that regard we have already given and undertaken to implement the recommendations in full."
One contributor at the EGM stated Welsh rugby was the laughing stock of world rugby, but insisted the blame should be laid at the WRU hierarchy and not the clubs.
"It was a comment well made," added Walker.
"We aren't ducking responsibility, we are responsible for running this organisation.
"We have not done as well as we could have in a number of areas. Now is the time for change."
The first step will be try to recruit the independent chair with Walker confident the WRU can achieve the deadline of 31 December, 2023 to enact the changes.
Once the new chair is appointed, current incumbent Ieuan Evans will step down and a permanent chief executive will be recruited.
Walker was asked whether he would like the role full-time.
"I haven't even given that a thought," added Walker.
"I've all the things I'm thinking about, how long I am interim CEO is not one of them.
"It may sound twee, but it is bigger than any one person, it is about the game as a whole."
Evans was reflective on being voted out of his chair role.
"I loudly applaud them for voting me out of office," added Evans.
"I have no doubt there will be people who want to become the new independent chair of the WRU.
"We are fortunate in Wales. Sometimes we take it too lightly at how significant a role Welsh rugby and the WRU plays in Welsh life.
"It is embedded in our DNA and plays such an important role in our civic and social lives.
"I feel this is a wonderful opportunity for a person with drive, enthusiasm and skill set to play a massive role in our future."