Fischer assists clients in the US and internationally with transactions, copyright and patent licensing, trademarks, arbitration and litigation involving information technology, the Internet, new media and social networking, software, interactive entertainment, electronic publishing, mobile devices, DVDs and gaming. He also serves the biotechnology and medical industries. Fischer drafted the first open source software agreement and litigated the first moral rights lawsuit in Massachusetts. Widely known in the field of entertainment law, his clients have included Oscar-winning documentary filmmakers, Grammy winners and best-selling authors. At Fish & Richardson he was chair of the firm's New Media & Entertainment section and he co-chaired the Copyright section.

He teaches Advanced Copyright at Suffolk University Law School and has been an adjunct faculty member teaching entertainment law and IP courses at Berklee College of Music, Boston College Law School, Northeastern University School of Law, and New England School of Law. Fischer is a frequent speaker on digital copyright issues, social media and entertainment law at national media and legal conferences. He is a former Trustee of the Copyright Society of the U.S.A. and co-founded the organization's New England chapter.

Fischer has been listed in The Best Lawyers in America in every edition since 1993. He was named by IP Law & Business to its "The Best Lawyers" list in Entertainment Law from 2004-2008. He was described in Boston Magazine as one of "The Best Lawyers" and described as "a trailblazer in the field of new media." He has been listed in Super Lawyers in Massachusetts every year since 2004.