[3][6] Dwinelle represented the city of San Francisco in the so-called "pueblo case", Hart v. Burnett, which secured San Francisco's claim to four square leagues of land due to the city's establishment as the pueblo of Yerba Buena under Mexican rule.

The Supreme Court of California ruled that black students could not be refused education under the Fourteenth Amendment, but that they could be denied entry into specific schools on the basis of race.

[3][11] Although Dwinelle represented both black and Chinese clients during his career, he was progressive for his time only when it came to the civil rights of African Americans.

[3] In 1876, Dwinelle vehemently denounced Chinese immigration in testimony before a joint special committee of Congress which was visiting California to investigate the matter.

[3][12] Dwinelle should have known better, since in 1862, he himself had successfully represented Chinese clients in a civil action to challenge a "coolie tax" enacted by the state legislature.