Harry L. Osias was a prominent real estate developer and builder active in New York City and Miami during the mid-20th century. His career spanned several decades and left a notable imprint on residential development in both regions. Osias was known as a hands-on builder and community supporter, often engaging directly with tenant councils and local leaders. His developments were part of the broader trend of affordable, multi-family housing in the 1940s–1960s, catering to middle-class families. He served as the President of the Associated Builders of Greater New York for six years in the 1940s.

• ​He was the builder and developer of the Kew Gardens Hills Apartments in Queens, New York, as well as The Douglaston Towers project, The Commodore at 135-09 83 Avenue, The Coronet with architect Oscar I. Silverstone and many more throughout Brooklyn, Queens and the lower east side of Manhattan.

• He was listed as the owner/agent for developments overseeing everything from construction, to financing and tenant relations playing a key role in community initiatives, including donating space for a nursery school and supporting tenant-led programs.

• His work contributed to the post-war housing boom, especially in suburban-style apartment complexes.

• His buildings typically emphasized durability, modest elegance, and practical layouts.

While Harry Osias’s most documented work was in New York, he extended his building and development efforts into Miami during the mid-1900s. His move aligned with the post-war boom and migration trends that transformed South Florida into a hotspot for residential growth.