It was at Miss Chapin's that Isabella would meet Eleanor Roosevelt, eventually being a bridesmaid for Eleanor when she married Franklin D. Roosevelt.

In July 1905, Isabella married Robert Munro Ferguson, a former Rough Rider with Teddy Roosevelt. Teddy would attend this wedding, riding over from his Sagamore estate. Robert, having contracted tuberculosis, moved his family west. In 1923, Robert died leaving Isabella and their two children Robert and Martha.