In addition to performing autopsies on the victims, Ducky can now compose a psychological profile on any potential suspects or criminals that the team encounter, having graduated after taking a forensic psychology course.
His current assistant is James Palmer who became the permanent replacement for Ducky's previous assistant, Gerald Jackson who temporarily resigned after he was held hostage and shot in the arm by terrorist Ari Haswari in the Season 1 episode, Bête Noire (episode) and who later resigned from NCIS for good after Ari captured Gerald yet again in the Season 3 episode, Kill Ari Part 2 (episode).
Ducky lived with his mother until her sudden death, in a large mansion of the classical American style of architecture popular in the antebellum Southern United States. In Hiatus Part 2 (episode), Ducky mentions that she left him on a bus as an infant, and was halfway to her destination before she noticed he was gone. Mrs. Mallard died in 2010, a month before the events in Double Identity (episode). After his mother's death, Ducky put her house on the market for sale, and began the process of buying a historic brownstone in Georgetown. He also ensured that her beloved Corgis were adopted by a loving family.
Ducky has a tendency to tell rambling anecdotes from his past or make comparisons with some unusual field of study when they remind him of something that is happening around him in the present, which is often. He also speaks frankly to the bodies that he examines in the morgue, carrying on in a casual and friendly manner to the corpses as if they were alive and listening intently to him.
Ducky was educated at Eton College, and subsequently graduated from University of Edinburgh's Medical School, not only did he attend Kings College, Cambridge for a year before leaving to go to medical school he started to study English Language and History. Additionally, Ducky successfully completed a Masters degree program in the field of forensic psychology.
Prior to joining NCIS, Ducky worked with several other organizations including the British police before coming to the US and joining NCIS. Ducky by his own volition affirmed that he served in the military during the Vietnam War, although whether he served in the American military is unknown. In Season 4, Episode 9 Ducky made reference to serving as an officer in "The Regiment", implying he served in British SAS.
In 1980 Doctor Mallard was working in a refugee camp in Afghanistan, and while, there he became acquainted with Polish born CIA interrogator, Marcin Jerek who was known locally as "Mr. Pain." As a result of this acquaintance Ducky was later mistakenly charged with war crimes for violating Article Four of the 1949 Geneva Conventions by the government of Afghanistan in Broken Bird (episode). When the truth surrounding the events was revealed through the efforts of Gibbs and the team who arranged a meeting between Jerek. During Ducky's confrontation with Jerek it was revealed that Jerek was trying to break Ducky whose status a doctor was a beacon of hope for the refugees. Jerek tortured an innocent man who would then be sent to Ducky for medical care. Under stress Ducky eventually made the decision to end the young man's suffering by giving him an overdose of morphine which apparently caused his death a decision which would haunt Ducky for years. As a result of the confrontation with Jerek that resulted in Jerek's admissions to torture the charges against Ducky were dismissed. The emotional toll on Ducky was immense and at the end of the episode he is seen crying in the morgue after Palmer demonstrates his comprehension of the lesson that Ducky was trying to teach. He is consoled by Jordan Hampton.
Dr. Mallard has worked as the Medical Examiner for NCIS for at least seventeen years because, the events are chronicled in the sixth season episode Silent Night (episode) involve a Marine who was believed to be deceased due to a mistaken identification performed using only dental records seventeen years ago.
Dr. Mallard has also obtained a degree in forensic psychology and often provides psychological profiles of suspects for the team.
In the Season 9 finale, Till Death Do Us Part (episode), Dr. Mallard was walking along a shore near the site of Palmer's wedding, when he got the news that the Navy Yard was blown up and there were multiple casualties. However, in the middle of the call, Dr. Mallard collapsed due to an apparent heart attack.
In "Extreme Prejudice", it is shown that he was alive and receiving treatment thanks to Palmer finding him. He soon recovered from his heart attack, and under reduced workload, returns to work, eventually returning to his position as the NCIS Medical Examiner.
When he was first introduced in the two pilot episodes for NCIS, Ice Queen (episode) and Meltdown (episode), Ducky was something of a dirty old man, regularly hitting on fellow colleague Vivian Blackadder as he attempted to ask her out to dinner but Viv always turned him down, stating that she never went out with men old enough to be her father.
Ducky's nickname comes from 2 factors. One from his first name, Donald, the same as the well loved character from Disney, the duck "Donald Duck." Also, his last name is Mallard, which is a certain breed of duck.
However, when NCIS went solo, Ducky had stopped hitting on his colleagues and became more mature, developing a habit of talking to the corpses, a trait which had disgusted Blackadder who had also claimed that Ducky had a lack of respect for the dead.
During Seasons 1 and 2, Ducky always aided the team whenever it came to Autopsies and often provided them with a cause of death. He also had a habit of changing subject and rambling on about a story, forcing Gibbs to get him back on track. He has also displayed a fierce protectiveness of his Medical Assistants as seen when he tended to Gerald Jackson who was shot in the left shoulder by Ari Haswari in "Bête Noire"
In the Season 3 premiere episode, Kill Ari Part 1 (episode), Ducky personally performed the Autopsy on Special Agent Caitlin Todd who Haswari had murdered in the last few seconds of the Season 2 finale, Twilight (episode).
Like the other members of the team, Ducky too had a talk with Kate's ghost and she told him how she hadn't been able to bring herself to stab Ari because when she'd looked into his eyes, they had seemed kind and that there was something in them that had made her unwilling to kill Ari but Ducky told her that when he himself had looked into Ari's eyes, they looked like ice to him.
In Season 4, Ducky successfully obtained a degree in Forensic Psychology, a role that Agent Todd had previously fulfiled on the team up until her murder. He and Gibbs also had a hostile relationship due to the fact that Gibbs had not told him about his first wife, Shannon and daughter, Kelly. But in "Smoked", the two eventually made up with each other and resumed their friendship once again.
Ducky is a clear polymath and is described by DiNozzo as having an encyclopedic mind that is at times connected directly to his mouth. His rambling about what he knows often frustrate many members of the team especially Gibbs who notheless remains his closest friend. It can however come in useful at times such as when Ducky discovers a cause of death when he remembers that a suicide pile was created by the ingredients that showed up in a deceased man's blood by the CIA for its operatives.
Relationships with Other Characters
Leroy Jethro Gibbs
Ducky and Gibbs have a longstanding friendship that dates back to the period when Jethro and Jenny Shepard were partners in France, because he and Jethro escaped in a boat procured by Jenny. Ducky's friendship with Jethro was further reinforced when after Gibbs returned to NCIS after coming out of semi-retirement, he apologized to Ducky for his actions after he came out of the coma.
Also during "Hiatus" Gibbs was in a coma he was the only one there when he awoke. In that same episode, DiNozzo commented that if Gibbs didn't remember Ducky he wouldn't remember anyone.
Additionally, he is one of the few people who regularly calls Gibbs "Jethro" apart from Jenny Shepard, Tobias Fornell, and G. Callen.
Dr. Mallard adopted a fatherly attitude toward Kate Todd. He repeatedly refused to call her Kate, preferring to call her Caitlin just like Ari Haswari who would be responsible for Kate's death.
When Kate died after being shot in the head, Ducky was seen grieving over her body in the morgue and told Kate that he was so sorry.
In addition, Ducky also personally handled Kate's autopsy, refusing to let another Medical Examiner do it. Like the other members of the team, he had a vision of her talking to him and she told him that she should have killed Ari while also voicing a belief that she did not deserve to die.
Donald and Ziva have a very good relationship, most likely because she saved his life when the two were being held hostage by Elaine Burns in "Silver War".
He refers to her as his friend in 'Good cop, Bad Cop' and shows concern over her mental state during the 2nd, 3rd and 4th episodes of Season Seven. They drink tea together in 'Witch Hunt'.
They both comment on Tony's bad English in 'About Face,' as Ziva's English is closer to "Queen's English" (English spoken in Britain), which Ducky would speak.
They have a very good friendship, this is seen in numerous episodes where they joke and laugh and comfort each other. They also seem to have friendship due to the common bond of their profession. He is also the only person to call her by her full first name Abigail although Abby has expressed dismay at being called that.
Ducky's relationship with Jimmy is akin to the relationship that exists between a father and a son. In this way Ducky's and Jimmy's relationship parallels the relationship between Gibbs and DiNozzo, with the elder mentoring the younger: Ducky through his stories, and Gibbs through his rules. Jimmy is one of few people close to him that calls him "Dr. Mallard" instead of "Ducky" and by the same token Ducky usually addresses Jimmy as "Mr. Palmer"; however, Ducky has been known to call Jimmy by his full name when concerned for him.
There is a bit running gag where they are usually late to a crime scene due to Jimmy's driving and his tendency to get lost, much to Ducky's fustration. To a certain extent Jimmy has developing Ducky's trait of storytelling while working on cases, as demonstrated in episode 6.20 ("Dead Reckoning") when Jimmy and Ducky engage in a discussion about harmony.
At some point in the past Dr. Mallard had a brief liaison with Agent Sharp. Mrs. Mallard disliked Agent Sharp although, the reason for her dislike is not elaborated upon. It was also noted by Sharp that her husband hated Ducky and Ducky confirms that he hated him too. Ducky called the affair 'one moment of weakness'.
Ducky is very polite to the corpses as he can often be seen talking to them. He asserts that he does this to counteract the invasiveness that characterizes the nature of his work. He even calls them his "guests".
- Ducky is the first ever main character of the NCIS team to have been been featured in a Foof when it was introduced in the Season 2 episode, Lt. Jane Doe (episode).
- David McCallum is best known by many fans for his work in the 1960s series, "The Man from UNCLE".
- Ducky's car of choice is a Vintage Morgan which was revealed in the Season 3 premiere episode, Kill Ari Part 1 (episode).