Announced during a Property Council breakfast in Perth, the premier said it would be established in early 2019, after a year of consultation and enabling legislation.
The independent board - to be made up of leading public and private sector industry figures, including a private industry chairman - aims to develop a 20-year plan for WA's infrastructure and industry investment, which is intended to become an apolitical guide to state and federal government funding.
It will also provide advice on financing and funding options, and improve collaboration with government, community and industry on infrastructure.
According to McGowan, for too long the state's multi-billion infrastructure spend has been held hostage to political cycles, resulting in a lack of long term planning.
"There will be less silo decision-making across portfolios rather than each portfolio and minister making decisions without reference to a greater plan," McGowan said.
"What I want to do is milk as much as I can out of the Commonwealth for Western Australia - the other states do it and this body will let us do that.
"With Infrastructure WA our state is set for a major change. It will take us forward and make sure we spend the right money in the right place at the right time."
Infrastructure WA aims to protect the design and funding of major projects from the election cycle, and end the uncertainty hobbling the property, engineering and related industries.
With its launch, WA falls into line with NSW, Queensland, Victoria and Tasmania, which all have equivalent bodies. South Australia's Liberal party has promised one if elected next month.
The independent statutory body will vet infrastructure proposals of state significance, that is, for projects costing $100 million plus, or smaller but high-risk projects.
The projects might be government or private sector proposals or joint proposals, and evaluation will include consulting communities and evaluating business cases, including cost-benefit analyses.
From its evaluations, Infrastructure WA will form an overarching priority list of major projects covering a period of at least 20 years, with an overall update every five years, to inform state spending decisions and lobby for federal funding.
"Infrastructure WA would be an independent body to provide scrutiny for important, complex and high value projects that would restore the public's confidence in government decision-making," McGowan said.
"I would expect political parties of all stripes, their infrastructure commitments will start to align with the strategy, which will largely become a bipartisan document over time.
"Where politicians now or in future decide to reject its advice, they will be required to account for those decisions."
McGowan has encouraged the construction, planning and property sectors to submit feedback.
The state government's current biggest capital works project is the multi-billion dollar Metronet rail development, including a new connection to the airport and new lines into growing areas.