Guy Flynn represents parties in all areas of commercial real estate investment, development, leasing and finance.

His clients include institutional investors, pension funds, developers, lenders, borrowers, underwriters, and other public and private business entities in various commercial transactions, including joint venture, acquisition and development, leasing, commercial finance, purchase and sale, workout, foreclosure, syndication and PropTech transactions. Guy also counsels clients with respect to land use regulation, taxation, environmental, corporate, and bankruptcy issues.

The respected English research firm Chambers & Partners perennially lists Guy in Chambers USA, noting that he is "outstanding," "is widely respected in the market," "is commended for his expertise in commercial real estate development and finance," is "very knowledgeable about commercial real estate tax issues and structures" and "adept at handling large transactions." Chambers has also noted "his involvement in a series of high-profile and high-value transactions in Maryland."

In May 2019, Guy was inducted into the Maryland Chamber of Commerce Business Hall of Fame in recognition of his outstanding contributions to the state's business community that have helped advance the quality of life for Marylanders and the state's business climate, and for his professional achievements, community service and mentorship within Maryland's legal, civic and philanthropic communities. In July 2019, Guy was named to The Business Journals' "Influencers: Law" list, which spotlights 100 notable attorneys nationwide who are driving business for their employers, and for their clients, in cities across the country. In March 2013, the Daily Record named Guy to its 2013 Influential Marylanders list. The list recognizes individuals who have made significant contributions in their fields and are regarded as leaders in Maryland. In November 2013, Guy was awarded a 2013 Leadership in Law Award from the Daily Record in recognition of his outstanding professional achievements, community service and mentoring within Maryland's legal community. In November 2016, Guy was honored by the Israel-based Bnai Zion Foundation for his work as a legal and community leader in the greater Baltimore area.

Repeatedly since 2007, Guy has been named a Maryland Super Lawyer by Law & Politics and Baltimore magazines. In June 2003, he was named a Legal Eagle and one of the Baltimore region's top lawyers by the Baltimore Business Journal. In June 2001, Guy was named one of Baltimore's "40 Most Successful Young Professionals" by Baltimore magazine. Based on peer reviews, Guy is listed in The Best Lawyers in America in the category of real estate.

Guy is past chairman of the Maryland State Bar Association (MSBA) Real Property Section Discussion Group, a monthly gathering of leading real estate lawyers in the state for discussion of topical matters. From 2001 until 2011, Guy served on MSBA's Real Property Section Council, which is the governing arm of MSBA's Real Property Section. Currently, Mr. Flynn serves on MSBA's Real Property Section Legislative Liaison Committee, which tracks and provides comment to legislation affecting real property interests in Maryland.

Guy serves in numerous leadership roles within Maryland's civic, philanthropic and arts communities, including his current service as president of the Board of Trustees of the Walters Art Museum; a member of the Board of Trustees and Executive Committee of the Baltimore Community Foundation; a member of the Board of Trustees of the Living Classrooms Foundation; a member of the Boards of Directors of Maryland Legal Aid, The Center for Urban Families (emeritus member) and Baltimore Efficiency & Economy Foundation; and a member of the Board of Governors of The Center Club (Baltimore's premiere business club).  

In June 2020, Guy was appointed by the Maryland Attorney General to the newly formed Maryland Attorney General’s COVID-19 Access to Justice Task Force, where he was also named Co-Chair of the Task Force’s Pro Bono Committee. From June 2010 until January 2020, Guy served as a member of the five-person Baltimore City Board of Ethics, where he served after being appointed by Baltimore's mayor in 2010.