De Witt was born in New York City, NY in 1818 to Peter De Witt, a lawyer on Nassau Street. He was the clerk at Eli Hart &
Co., a flour merchant, in 1837. During the Bread Riot of February 1837, De Witt single-handedly saved the firm’s records by
carrying them to his father’s office (from Washington Street to Nassau Street, a journey of approximately 1 mile). In the
1840s he held a seat on the New York Stock Exchange, but in 1848 he sailed for San Francisco on the steamer The Panama with
a cargo of merchandise, arriving on September 23, 1848. He established the commission house De Witt & Harrison at 187 Sansome
Street. He maintained several storefronts which sold, among other things, cement. He joined the Society of California Pioneers
in 1853. Their store at California and Front Streets suffered nearly $3100 in damage after the October 21, 1868 earthquake.
In 1854 he opened a branch in New York City which was later renamed De Witt, Kittle & Co. (After his retirement the firm changed
to Kittle & Co., with offices located at 88 Wall St.) He died at his country estate in Staatsburg, NY in October 1899.