Richard Bennett Carmichael was born the only son of William and Sarah Downes Carmichael to an old and wealthy Maryland family in Centreville, Queen Anne County on December 25, 1807. His father had shared rooms in Annapolis with future chief justice Roger Brooke Taney and the two men remained friends till William died in 1853. Richard was schooled locally and then entered Dickinson College in Carlisle, Pennsylvania with the class of 1827. While at the College he was elected to the Union Philosophical Society in 1825 but withdrew later to attend Princeton, where he graduated in 1828. He subsequently studied law and opened a practice in his home town in 1830.
Almost immediately after starting his legal career, he was elected to the Maryland house of delegates and two years later, at the age of twenty five, was elected to the United States Congress as a Jacksonian Democrat. He served one term, returned to Centreville, and later, in 1841, went again to the state house, where he served multiple terms over more than two decades. He remained very active in Democratic politics, acting as a delegate to the party's national convention. in 1856. In 1858 he was appointed an associate justice on the 10th Judicial Circuit that encompassed four local counties on the Eastern Shore of Maryland, including his own.
In 1855 Carmichael, a slaveholder, had been at the center of a celebrated runaway slave case when Phoebe Myers, a free African-American woman in Queen Anne County, was sentenced to more than forty years in prison for harboring two of Carmichael's slave families who had fled bondage. Carmichael, who could afford to be magnanimous and who was a devout Episcopalian, helped petition the Maryland governor for clemency and Myers was pardoned in May 1856, having served less than five months.
In an even more celebrated case, Carmichael himself was to experience life behind bars when in on May 27, 1862, federal officials dragged him from his bench in the Talbot County circuit courtroom, according to some reports, pistol-whipped and bloody, and threw him into a military prison as a subversive and Confederate sympathizer. Carmichael, a strict constructionist following very publicly Chief Justice Taney's opinions on arbitrary arrest, had long resisted President Lincoln's suspension of habeas corpus often directing grand juries to indict the officials who carried out arrests without warrant. General John Dix, military governor in the area, lost patience after some months of this and ordered his arrest and incarceration without trial. Held at Fort McHenry, then Forts Lafayette and Delaware, Carmichael constantly demanded release or trial, even writing Lincoln personally, but got neither. When he was set free after more than five months, he attempted again to direct grand juries as he had before but by this time the state was under solid Union control and citizens serving on these juries returned no indictment. Disheartened, Carmichael eventually resigned from the court in 1864. Following the Civil War, he again involved himself with Democratic politics. He continued to serve as elector at the national conventions of 1864, 1868, and 1876, and was the president of the Maryland constitutional convention of 1867.
He had married his eighteen year old cousin Elizabeth Margaret Hollyday in 1835 and the couple had seven children. Elizabeth died in January 1883, ending almost forty-eight years of marriage. On October 21, 1884, Richard Bennett Carmichael died at his home "Belle Vue" on the Wye River and was buried in the family plot there. He was seventy six years old.