While later in life he changed his surname to Simpson, he was born Charles J. Sismilich in July 1893 in New York City (not to be confused with his younger first cousin, Charles J. Sismilich of Jersey City, NJ). Charles was the grandson of Frantisek (Frank) Sismilich, who brought his family to the United States in 1868 from Klisinec, Bohemia, and the son of the eldest son, Frank. As a young man, Charles had artistic talent which he displayed in a risqué manner by drawing pictures of naked women and hanging them up in the living room of his parents' home! He also appears to have been a boisterous character not terribly constrained by the social conventions of the time; one time on the streets of Yorkville, Charles spotted his aunt, Josephine Sismilich, on the street, snuck up behind her, and pounded her on the back, loudly saying, "Aunt Jo, you old son of a bitch!".

While Franklin D. Roosevelt was Governor of New York from 1928 to 1932, Charles became his chauffeur. During this time, Charles was living at 136 W. 65th Street. Unfortunately, no stories of his relationship or adventures with the great FDR have survived. It was said that he did not accompany FDR to the White House when he took office in the difficult days of the Great Depression in 1933, but the reasons why are not known.

One possible reason why little else is known about Charles is the widespread family disapproval that was said to have surrounded his name change from Sismilich to Simpson, which probably was done after April 1942. It is likely that he changed his name to avoid arousing the anti-German sentiment directed toward those with German-sounding names during the war, or perhaps it was in an attempt to make getting a job with the Roosevelt administration easier during wartime.

Nothing else is known of Charles' life, who perhaps should be the best known because of his connection with FDR. Charles and his five siblings (Mary, Ottilia, Anna, Frank, and George) are the lost tribe of Klisinec Sismilichs; nothing is known of their descendants. It is possible that Mary and George died at an early age since no family members alive in the past 25 years knew of them. There was speculation that Ottilia married and moved to Connecticut, but there is no evidence of this. It has also been said that Anna was going out with a Frenchman, but then wound up marrying his father instead and moving to France!