Rosenbaum was born to a Jewish family in Toledo, Ohio and attended Whitmer High School, the middle child of three brothers.In 1982, he was named vice president of the Dyson-Kissner-Moran Corporation, a private investment firm that pioneered leveraged buyouts.[11][12] From 2003 to 2010, he was the Chairman of TVC Communications, LLC, a distributor to the broadband industry, until its purchase by WESCO International.In 2014, Rosenbaum was one of the lead investors in a group that purchased the Dayton Dragons, the Class A-Advanced minor league affiliate of the Cincinnati Reds, from Mandalay Sports Entertainment.[14][15] In 2016, Rosenbaum purchased a minority interest in the Mahoning Valley Scrappers, now in the MLB Draft League.[30][31] In 2007, the Jewish Labor Committee granted Rosenbaum a National Trade Union Council for Human Rights Award.