Albert “Sonny” Abramson, a real estate developer who built many of the Washington area’s landmark office buildings and shopping malls and who was a driving force behind the design and construction of the U.S. Holocaust Memorial Museum, died March 6 at his home in Bethesda. He was 94.

He had pneumonia and renal failure, his daughter-in-law Anne Abramson said.

Mr. Abramson, who lived most of his life in or near Washington, launched his business, the Tower Companies, with a $500 investment in 1947. It became one of the region’s largest real estate concerns.

He often teamed with other builders in projects, most notably Theodore Lerner, owner of the Washington Nationals baseball team. Together, they built the White Flint mall in Rockville and the Washington Square office building in downtown Washington.

“His visionary talent is evident on many corners of his hometown,” Lerner said in a statement. “He was a monumental man in every respect.”

Washington Square, on the southwest corner of Connecticut Avenue and L Street NW, remains one of downtown Washington’s most striking buildings 30 years after it was built. Mr. Abramson hired renowned architect Chloethiel Woodard Smith to design the sleek, glass-front office tower.

“He wanted to create a building you could see inside,” his son Jeffrey Abramson said Wednesday. “That’s why it has the glass atrium. He wanted to bring the life of the building out into the street.”

Mr. Abramson was, by all accounts, a quiet and dignified man who shied from the public spotlight and never gave interviews. But he made a significant contribution to public life with his behind-the-scenes work on the planning and construction of the U.S. Holocaust Memorial Museum in the 1980s and early 1990s.

“We very much owe our existence today to Albert Abramson,” Sara J. Bloomfield, the museum’s director, said Wednesday in an interview. “He played a singular role in the development of the museum.”

When Mr. Abramson joined the museum’s planning committee in the mid-1980s, a building design had already been approved, although few were happy with it. As chairman of the building committee, Mr. Abramson firmly let it be known that the flawed, inadequate design would have to be scrapped.

“That took a lot of courage,” Bloomfield said. “It meant a delay, but he was interested in getting it right.”

Mr. Abramson arranged the hiring of architect James Ingo Freed, who went on to design an innovative museum that has won international acclaim since it opened in 1993.

Mr. Abramson also took a strong interest in the museum’s displays and general tone. He was chiefly responsible for hiring Jeshajahu “Shaike” Weinberg, the founding director who designed the memorable exhibitions that have made the museum an emotionally wrenching experience for many visitors.

Besides contributing millions of dollars to the museum, Mr. Abramson donated a sculpture that stands near the entrance. He and his late wife, Ruth, sponsored several educational programs and endowed the museum’s archives.

“He is definitely one of our largest single donors,” Bloomfield said. “He was a quiet, unassuming man who didn’t want attention, but he was determined to build this museum.”

Albert Abramson was born July 6, 1917, in New York City and came with his family to Washington when he was 4. His father ran a clothing store with several brothers.

Mr. Abramson was called “Sonny” by his mother and kept the nickname throughout his life. He was a graduate of the old Central High School, where was a member of the debate team. He received a law degree from George Washington University in 1939.

He served in the Army Air Forces during World War II and reached the rank of captain. He founded Tower Companies with two business partners, Henry Reich and Bernard Libby, but soon became the firm’s guiding force. The privately held business, based in Rockville, is now run primarily by Mr. Abramson’s three sons.

His wife of 64 years, Ruth Selsky Abramson, died in 2006. Survivors include three sons, Gary Abramson of Potomac, Jeffrey Abramson of Rockville and Ronald Abramson of Washington; a sister; five grandchildren; and three great-grandchildren.

Mr. Abramson was a trustee of several academic and charitable institutions, and he and his family were known for their philanthropy to colleges, museums and Jewish organizations.

“He never wanted public recognition, never,” the Holocaust Museum’s Bloomfield said. “He just wanted to do the right things for the right reasons.”