- National Sports Law Institute at Marquette University Law School – Executive Director (1989-1998)
- Built the area of sports law to a recognizable academic level and made the Marquette University law program the best and most comprehensive in the United States.
- National Sports Law Institute at Marquette University Law School – Chairman of the Board
- Wisconsin State Fair Park and Wisconsin Exposition Center – Chairman Appointed by Governor Doyle
- Southeast Wisconsin Professional Baseball Park District (Miller Park)
- Appointed to an at-large seat by Governor Doyle.
- Marquette University – Athletic Board
- Wisconsin Sports Development Corporation – Chairman of the Board
- Wisconsin Athletic Hall of Fame – Chairman Selection Committee
- Wisconsin Sports Authority – Founder and Secretary/Director
- Facilitated the acquisition of the Wisconsin Athletic Hall of Fame from the Wisconsin Center District.
- Wisconsin Sports Foundation – President
- State of Wisconsin Athletes Agents Advisory Committee Member
- Assisted in drafting the Wisconsin Sports Agent legislation.
- City of Milwaukee Task Force on Zoning Law Revisions – Committee Member
- Milwaukee City Attorney’s Office – Drug House Legislation Committee Member
- Village of Bayside Water Trust – Committee Member
- Village of Shorewood Board of Review – Committee Member
- Wisconsin Real Estate Examining Board – Book Revision Committee Member
- Make-a-Wish Foundation Host Night – Co-Chair
- Milwaukee Symphony Ball – Co-Chair
- Zoo Ball XIII “Cats” – Co-Chair
- Windows on Stritch – Co-Chair
- Milwaukee Symphony – Board of Directors
- Jewish National Fund – Board of Directors
- Marquette University Law Alumni Association – Trustee
- Marquette University Woolsack Society – Board of Directors
- Law Projects, Inc. – President
Here is a sample of the many organizations Martin J. Greenberg has been affiliated with over the past 4 decades: