Josh Seadia, Principal

Josh approaches commercial real estate through a unique blend of both financial and technical skills. He obtained a computer science degree from Northeastern University and has been involved with various start-up tech companies in the late 1990s and early 2000s.

For more than 12 years, Josh was employed at Fidelity Investments, helping individuals with their financial and retirement goals. He worked closely with clients to simplify the often challenging world of investing.

Josh enjoys applying the same entrepreneurial spirit and focused approach toward the highly complex field of commercial real estate. Based in Needham, JMJ Commercial Realty is a member of the Charles River Regional Chamber of Commerce (formerly the Newton-Needham Regional Chamber) where Josh serves as the Chair of the Real Estate Committee, as well as an Ambassador for new businesses that have recently joined.

When he’s not working in commercial real estate, Josh can be found spending time with family and friends. He also loves playing acoustic guitar, a hobby and passion he has pursued for more than 25 years.

View Josh’s client testimonials

Adam Schertzer, Advisor

Adam joins JMJ as an experienced professional with over two decades of dedicated service at SAP, a global market leader in enterprise application software, where he was committed to ensuring customer success through innovative problem-solving. His expertise consists of developing creative methods and ensuring his clients receive the best possible solutions to their business challenges.  

Adam is eager to infuse his client-centric approach into his role at JMJ Commercial Realty. He is a member of BNI and currently serves as the President of his local chapter.

Outside of work, Adam finds joy in quality family time and indulging in musical pursuits.

View Adam’s client testimonials

Greg Costello, Advisor

Greg Costello is a real estate and infrastructure leader with 15+ years of experience turning complex projects into tangible results. He has led large teams with large programs consisting of site selection, leasing, development, and cross-functional execution across New England and Nationwide, building strong partnerships and delivering outcomes that balance strategy, financial discipline, and community impact. Known for his steady leadership and practical approach, Greg enjoys working at the intersection of people, property, and long-term value creation.

Outside of work, Greg is a proud girl dad of two and can usually be found outdoors or immersed in music — believing that the best perspective, like the best deals, often comes from stepping back and seeing the bigger picture.