Columbus & Over Group

Advisor Profiles

Mark Callahan

Real Estate Advisor

Mark has been working in Boston’s real estate development and construction industries since 2010. Currently, Mark is an Associate with CIM Group, focusing on large scale commercial and multi-family developments in the Boston area. Previously, Mark worked as a Project Manager for New Boston Ventures, one of the premier boutique real estate developers in Boston. Mark got his start in Boston with Suffolk Construction, and is also a licensed contractor in the state of Massachusetts.

Drawing upon his experience as both a developer and a contractor, Mark brings a unique perspective to all of his clients. His pragmatic approach and diligence make him an ideal adviser for any client.

Mark earned his undergraduate degree in business economics from Brown University and has a Masters Degree in Real Estate Development from MIT. Mark and his wife Katie reside in the South End.

Jeff Hamilton

Founder and Managing Principal


Jamie Gaines

Real Estate Advisor


Alice Markson

Real Estate Advisor


Drew Brassard

Real Estate Advisor


Tim McGovern

Real Estate Advisor


Phil Cohen

Real Estate Advisor


Is COG Right For You?

Interested in joining the COG team? At Columbus & Over, we value our agents just as much as we value our customers. Tell us why you would make a good addition to our team.