James W. Calvo was admitted to practice law in the state of Illinois in 1990, as well as the United States District Court for the Northern District of Illinois, and he is a member of the Federal Trial Bar. He started his career working as a sole practitioner on LaSalle Street in Chicago from 1990 through 1998, where he developed extensive trial experience and expertise in commercial real estate.

From 1998 to 1999, he served as general corporate counsel for real estate developer Metropolitan Real Estate Co. in Oak Brook, Illinois. In 2000, he founded Brownstone Development Company, LLC, launching a successful real estate development firm that has completed over $75 million in commercial real estate projects throughout the Chicago area, including the development of twelve freestanding drugstores for a major national chain.  In Naperville he was the developer of three Walgreens drugstores and the Duly Medical Center at Rickert Drive and Ogden Ave.

He is a founding partner of Ellsworth Partners, a commercial real estate investment company with a portfolio of office buildings concentrated in Naperville, Illinois, where he is also actively developing multifamily residential projects. In addition, he is a licensed Illinois real estate broker.