She will start at the end of January, leaving her position as head of strategic projects development at the Energy Saving Trust.
Until she joins Julie Nicholas, CIH Cymru’s policy and public affairs manager, is acting as interim director.
Keith Edwards stepped down after 14 years at the helm at CIH Cymru earlier this month.
Northmore said: “I’m very happy to be joining CIH Cymru at such an important time for housing in Wales.
“I’m looking forward to working with colleagues and board members from across the organisation to make sure that the voice of CIH members is heard as we work towards our vision of a housing system that works for everyone.”
Before moving into her current role, she was head of Energy Saving Trust Wales, account director at Grayling Wales and deputy head of public affairs at the Federation of Small Businesses Wales.
Northmore has also been a non-executive director at Groundwork Wales since 2008.
Gavin Smart, CIH deputy chief executive, said: “We are working hard to strengthen our offer to members and Helen has a pivotal role in ensuring a strong, independent voice for housing in Wales.”
And Stephen Cook, CIH Cymru board chair, added: “It’s an incredibly important time for housing in Wales as the government here implements its first ever Housing Act and I know that Helen has the skills and experience we need to make sure that we are delivering the best possible support for housing professionals across Wales.”