Combining development and brokerage, Mark is responsible for leading the development and sale of over $135 Million of real estate transactions primarily in NYC, Greenwich CT, and New Zealand.  The OB Team consists of 4 licensed real estate agents led by Mark and Mark O’Brien Development has been building, restoring, and renovating homes since 1999.  

With over $45,000,000 in ground up construction, with experience using modular and precast construction, historic Brownstone restoration and residential renovations, recognized by the HOBI Awards and Press in Life and Leisure, Remix Magazine, Huffington Post, and Home Style Magzine.

As a dynamic and well-rounded real estate veteran, Mark brings a keen eye for value and opportunity to each and every engagement, attributed to my strong background in residential property development, building and business. Having lived and worked in New York City for more than 30 years, Mark offers experience of the all-important, yet often imperceptible, nuances of each neighborhood. Finding the city's hidden gems is one of my greatest passions, and am driven by creating real value on behalf of my grateful and loyal clientele.

Prior to real estate, Mark Founded and built Network Dynamics Inc. in 1986, an Executive Search and Consulting Business headquartered in NYC with 16 employees and over 150 contract consultants on staff with clients such as IBM, EDS, and Merryll Lynch. Sold in 1999 and launched into residential development and brokerage. Graduate of Iona College in New Rochelle, NY