[2] He was the son of James Roosevelt I (1828–1900) and his first wife, Rebecca Brien Howland (1831–1876), who were second cousins.

[3] When his father died in 1900, the family's estate was split between Rosy and his half-brother, Franklin.

[1] Throughout his life he was considered "an aimless if charming member of New York society's sporting set.

[1][6] Roosevelt was a trustee of the Cathedral of St. John the Divine and a close friend of Cardinal Patrick Joseph Hayes.

[1] On May 7, 1927, Roosevelt died at his Hyde Park home as a result of complications related to bronchitis and asthma, according to news reports at the time.