Mark D. Lerner is an American real estate developer and business executive, serving as the managing principal of Lerner Enterprises, the family-owned real estate firm founded by his father, Theodore N. 'Ted' Lerner in 1952. Born into a prominent Jewish family in the Washington, D.C. area, Lerner earned a Bachelor of Arts in Economics from Duke University in 1984 and joined the family business after college. He has been instrumental in its growth into one of the largest privately held real estate companies in the United States, managing a portfolio of commercial, residential, and mixed-use properties valued at billions of dollars, with over 20 million square feet of space across the Mid-Atlantic region. Key developments include high-profile projects such as mixed-use properties in Tysons Corner, Virginia, Chelsea Piers in Washington Harbour, and commercial spaces in downtown Washington, D.C. Following Ted Lerner's death on February 12, 2023, Mark assumed a more prominent leadership role alongside his siblings, including sisters Debra and Nancy, overseeing the company's operations and strategic expansions.

Lerner is also a key figure in sports ownership, serving as Co-Managing Principal Owner of the Washington Nationals MLB franchise (acquired by the Lerner family in 2006 for $450 million) and as Managing Principal Owner of Major League Soccer's D.C. United since 2012. He has been involved in the Nationals' operations, including the construction of Nationals Park which opened in 2008, and led the team to a World Series championship in 2019. His business interests extend to partnerships, including financial collaborations with investor David J. Blitzer in sports and real estate ventures. Despite the family's immense wealth—with Forbes estimating the Lerner fortune at around $6 billion in 2023—Mark maintains a low public profile, emphasizing philanthropy through the Lerner Family Foundation, which has donated millions to support education, healthcare, Jewish community initiatives, and organizations like the Jewish Federation of Greater Washington and Duke University in the D.C. region.

No major legal controversies or scandals are publicly associated with Mark D. Lerner personally, though the family business has faced typical real estate disputes such as zoning challenges and tenant lawsuits, resolved through settlements. He has faced scrutiny over the Nationals' performance and stadium-related public funding debates. His influence networks are primarily within Washington, D.C.'s business, sports, and philanthropic circles, with connections to political figures due to the company's government-related developments. He resides in the Washington area with his wife, Cara. He is also a member of the board of directors for the Greater Washington Board of Trade and has been involved in urban planning initiatives in the D.C. metropolitan area. He is a member of the Board of Trustees for Duke University and has served on the board of the Federal City Council, a civic organization focused on D.C. development.