Known as "The Queen" or "The First Lady of Oyster Bay" by its Long Island residents, Ethel was instrumental in preserving both the legacy of her father as well as the family home, Sagamore Hill for future generations, especially after the death of her mother, Edith, in 1948.

During her family's years in the White House, Ethel tried to keep as low a profile possible because she did not seem to enjoy the attention as much as her half-sister Alice Roosevelt did.

She was also encouraged to maintain her low-key persona by her mother Edith, who believed that a woman only made the news to announce her birth, marriage and death.

When it came time to have her portrait painted, she did not choose to wear an evening gown and jewels, she wore her Red Cross uniform.

When she felt Black residents were being discriminated against, Derby formed a committee to bring low-income housing into Oyster Bay.

In 1960 Derby, along with her daughter Edith, made a seconding speech for the nomination of Richard Nixon at the Republican National Convention.