A good friend of actress Thelma Todd, she was at a dinner given in Todd's honor the night of Todd's mysterious death from carbon monoxide poisoning. Margaret was so distraught that she had to bow out of a picture she was filming Murder by an Aristocrat (1936). Marguerite Churchill was given her assignment.
A lesbian, she was relatively open about her sexuality within the Hollywood community.
Her close companion was actress Mary McCarty.
In 1936 she was romantically linked to Janet Gaynor.
Sister of actress Jane Gilbert.
Sister-in-law of actor William Hopper.