<Li> Seth MacFarlane as Ed Mercer, the captain of the Orville . Mercer was an up - and - coming officer, believed to be on the fast track to commanding his own heavy cruiser by age 40 . However, a year before the pilot, he caught his wife Kelly in bed with an alien . Since then, he was cited for becoming lax in his duties, including six instances of reporting to duty while hungover, but was informed that due to the size of the fleet and the retirement of the former captain, the Orville, a mid-level exploratory ship, was in need of a new commanding officer . </Li> <Li> Adrianne Palicki as Commander Kelly Grayson, the first officer of the Orville and Ed Mercer's ex-wife . The two divorced when Mercer caught Grayson in bed with an alien . Unbeknownst to Mercer, Grayson personally went to Admiral Halsey to plead her case to give her ex-husband a command, stating that despite some personal setbacks, he deserved his own command . She asked Halsey to keep that from him when assigned the Orville . Mercer and Grayson decide to put their differences aside, to work together as a team and stay as friends . </Li> <Li> Penny Johnson Jerald as Dr. Claire Finn, the Chief Medical Officer on the Orville, holding the rank of Lt. Commander . A physician of exceptional credentials, she has expertise in molecular surgery, DNA engineering and psychiatry, which could have afforded her the privilege of serving on the heavy cruiser of her choice . She instead chose the mid-level exploratory vessel because, as she explains to Mercer in the pilot, she prefers to request her transfers based on where she feels she is needed, as she feels more stimulated by such assignments . When she tells Mercer she felt he could use her help on his first command, he interprets this as lack of confidence on her part in his competence, though she denies this . Having never found the ideal opportunity to marry, she chose to become a single mother, and her two sons, Marcus and Ty, travel aboard the Orville with her . </Li> <Li> Scott Grimes as Lt. Gordon Malloy, the helmsman of the Orville and Mercer's best friend . Considered the best helmsman in the fleet, he was relegated to desk duty after an attempt to impress a girl resulted in him shearing the door off a cargo bay during a precarious shuttle docking, losing cargo in the process . He was specifically requested by Mercer despite some hesitation by Admiral Halsey, who harbors concern over Malloy's history of crude and juvenile pranks . </Li>

Who played the blue alien in the orville