Brown has been part of the wind power industry since 2000 and has previously worked for NEG Micon (bow part of Vestas), BVG Associates, Areva Wind, and most recently technical consultancy 8.2Aarufield.
MHI Vestas stated his appointment reflected the "increasing importance" of the UK’s offshore wind market.
CEO Philippe Kavafyan said: "MHI Vestas Offshore Wind has built a strong presence in the UK over the past four years, having created over 500 jobs in manufacturing, construction and services.
"We plan to expand further and are delighted to see Julian joining our team."
Brown began his career in aerospace and also ran businesses in the electronics and aircraft industries.
He entered the wind industry in 2000 and established the blades manufacturing facility on the Isle of Wight for NEG Micon.
Brown also co-founded wind power consultancy BVG Associates and 8.2Aarufield, which is part of renewable energy company, the 8.2 Group.
He is also a non-executive director of subsea cable company Tekmar and energy engineers 3Sun Group, and was a board member and chairman of trade association RenewableUK.
MHI Vestas’ CEO Kavafyan added: "Julian brings almost 20 years of dedicated wind experience and an extensive business and industrial network which will significantly accelerate our deployment in the UK."
The manufacturer has 349MW of operating capacity off the coast of the UK, according to Windpower Intelligence, the research and data division of Windpower Monthly.