Brandegee was born in
New London, Connecticut. He was the son of John Brandegee and Mary Ann Deshon Brandegee. His father was from a Connecticut family, and relocated to
New Orleans cotton broker; he later returned to New London and became active in the whaling industry and other business ventures. Brandegee was educated at Union Academy in New London and
Hopkins Grammar School in
New Haven. In 1845 Brandegee entered
Yale University, where he was elected membership to
Delta Kappa Epsilon and
Skull and Bones. He graduated in 1849, and then began studying at
Yale Law School. Brandegee completed his legal studies in the office of Andrew C. Lippitt in 1850, was admitted to
the bar in 1851, and began to practice in partnership with Lippitt. Brandegee was elected to the
Connecticut House of Representatives in 1854. Although a young member of the House, he was selected as a member of the important judiciary committee. He was also chairman of the select committee to manage the "bill for the defense of liberty," which was aimed at preventing the enforcement of the
Fugitive Slave Law in
Connecticut. Later, Brandegee chaired the committee which oversaw passage of Connecticut's version of the
Maine liquor law, which prohibited the sale of alcoholic beverages. From 1857 to 1859, Brandegee served as
Judge of New London's city court. During this time he became a popular speaker in favor of abolishing slavery, and he delivered speeches at locations throughout Connecticut. In 1860, he was chosen as one of Connecticut's
electoral college members, on the Republican ticket headed by former Governor
Roger Sherman Baldwin;
Abraham Lincoln carried Connecticut, and the electors cast their ballots for Lincoln for president and
Hannibal Hamlin for vice president. Brandegee was again elected to the Connecticut House as a
Republican in 1858. He was reelected in 1859, but declined the office because of the death of his father. He was elected as the
speaker of the Connecticut House of Representatives in 1861. During this first "War" session of the House, Brandegee managed to keep favor with both
Democrats and Republicans. At the end of the year, fellow
Bonesman and the leader of the Democrats in the House,
Henry C. Deming presented him with a silver service as a token of appreciation for his impartiality. At the start of the
Civil War, Brandegee was active in supporting the Union cause. He traveled all over Connecticut addressing meetings, raising troops and arousing public sentiment. ==United States House of Representatives==