(Portrayed by Rainn Wilson and Roger Carmel).

A human conman, rogue and trader/smuggler of the 23rd century, Mudd disappeared with his fiancee's dowery during the Klingon-Federation War. He was captured by the Klingons and later shared a prison cell with Captain Gabriel Lorca and Lt. Ash Tyler, but was left behind by the Starfleet officers. Mudd escaped and planned to steal the U.S.S. Discovery using a time loop but the conman was conned by Captain Lorca, Lt. Stamets, Lt. Tyler, and Science Specialist Burnham to allow the loop to expire. Unbeknownst to Mudd, the crew re-programmed the computer to send the ship's location not to his Klingon buyers, but to his fiancee, Stella, and her father, Barron Grimes.

Mudd later fled into galactic escapades to escape his shrewish wife Stella.

He was 6-feet-1 and 240 pounds, according to Police Record-Code X731248. In 2366, James T. Kirk helped send Mudd to a rehab colony after he was caught using the illegal Venus drug to beautify three women he hoped to sell to miners on Ophiucus VI as brides.

Mudd's offenses at that time had included smuggling, transport of stolen goods, and purchase of a space vessel with counterfeit currency; the first carried a suspended sentence, while the latter two were treated with psychiatric care whose effectiveness was later disputed. In any case, his ship master's license was revoked on SD 1116.4.

Within a year of the Venus drug incident, Mudd had escaped and already been sentenced to death by Denebians for selling them a fake Vulcan patent. Eluding that, he caught up with subterranean, ancient androids of a world he later named for himself; they later held him hostage along with Kirk's crew until the captives worked together to escape using illogic. Mudd was left on this planet with 500 copies of a Stella android.

Later in 2267, Mudd stole a spaceship and left for the world of Ilyra VI, where he sold the inhabitants the deed for Starfleet Space Academy. He then went to Sirius IX, and sold the populace there a love potion which made them sick. He escaped to the planet Motherlode to sell the same love potion to the heavy metal miners there, but he was really using a Rigelian hypnoid to fool them. Kirk and Mister Spock took Mudd into custody and returned him to the Enterprise, whereupon he caused havoc by giving Nurse Chapel some of his love potion to use on Mr. Spock. Surprisingly, the potion worked, but despite taking Chapel hostage and escaping in a shuttle, Mudd was ultimately apprehended, whereupon he gave a full confession of his latest crimes.