By 1877, 109 Commonwealth was the home of General Casper Crowninshield and his wife, Elizabeth Copley (Greene) Crowninshield. Elizabeth Crowninshield is shown as the owner on the 1883 Bromley map.

Caspar Crowninshield served in the Civil War from 1861, rising to the rank of Colonel. He served with Sheridan through all the campaigns in the Shenandoah Valley and in the Appomattox campaign, and was present at Lee's surrender. On May 20, 1865, he was brevetted Brigadier General and was mustered out of service on June 20, 1865.

Elizabeth Crowninshield died sometime between 1883 and 1888.

Caspar Crowninshield continued to live at 109 Commonwealth, joined in about 1893 by his son-in-law and daughter, landscape architect David Hill Coolidge, Jr. and Harriet Sears (Crowninshield) Coolidge. In 1892, they had lived in an apartment at 411 Marlborough Street .

Caspar Crowninshield died in January of 1897.