Dan Williams (also known as Danny or Danno) was a member of the Hawaii Five-0, the (fictional) elite state police unit of Hawaii, from 1968 to 1979.
If we assume that he shares the same birth date as his actor (1937) then Danno was 30 when we first met him, in 1968. At that time, he was the second-in-command to the unit’s head, Steve McGarrett, and he remained at that rank for the next eleven years.
There are differing opinions as to how Williams gained the position of Second in Command at Five-0. The majority of fans believe that he worked his way up through the ranks at HPD. Some, however, hold the opinion that (given his young age, and the time it would have taken for him to work his way up), he could have been recruited to the unit directly from college or the armed forces, and especially trained for the position.
At 30, some people would consider him young for the responsibilities of the rank. When we first met him, his inexperience and lack of self-confidence were sometimes painfully obvious. He was occasionally prepared to argue with McGarrett, if he felt that it was warranted, though he never won the arguments -- there was only one boss at Hawaii Five-0, and it was not Dan Williams.
As Williams gained experience and confidence as a police officer his willingness to challenge McGarrett’s authority diminished. Perhaps this was because, as he became more secure in his abilities, he no longer felt the need to assert himself by challenging his boss, or, maybe, he realized that arguing with McGarrett was pointless.
During his term with Hawaii Five-0, Williams gained skill in many facets of police work. From a shaky beginning, when he nervously defused his first bomb, following instructions shouted to him through the office door, he progressed to become Hawaii Five-0’s resident bomb expert, and was called upon to neutralize several more bombs during his career with the unit.
Williams was an expert marksman whose sharpshooting skill was utilized on many occasions. He was also acknowledged as a handwriting expert.
Williams’ youthful good looks, charm and ability to blend in with the people around him, made him a prime choice for undercover work, especially when it was necessary to get close to young people or women. Some of his more memorable assignments included posing as a soldier on leave from Vietnam in order to extract information about a murder victim from a young bargirl, and infiltrating a neo-nazi group to protect a political candidate.
Like most TV detectives of the ‘60s and ‘70s, information about Dan Williams’ private life is rather scanty, and riddled with inconsistencies. During his term with 5-0, he was wounded several times and held hostage at least twice; his fiancée and several of his friends were killed; his best friend manipulated his friendship in an attempt to escape detection for the murder of his wife, and an ex-girlfriend tried to set him up to kill her lover, yet there never seemed to be anyone, outside the tight-knit 5-0 unit, to give him support. No relatives or girlfriends waited anxiously for news when he was wounded or held captive. No family members gathered to support him when his fiancée was murdered, or his best friend betrayed him. Towards the end of the series, we learned that he had an aunt (who was played by James MacArthur's stepmother Helen Hayes), an interfering old busybody named Clara, who (much to his relief, I am sure!) lived somewhere on the mainland. But where was she, when he needed someone? There was never any mention of Dan’s parents or any siblings, so we assumed that his parents were dead, and that Clara was his only living relative. On the other hand, he seemed to have an affinity with children, and was able to handle children and babies competently, which seems unusual for a bachelor with no children in his immediate family.
In his free time, Dan was the coach of a kids’ baseball team sponsored by Hawaii Five-0.
In early episodes, he went surfing, but, as he aged, his interest in the sport seems to become restricted to judging surf competitions. He also played tennis, swam, sailed and rode horses.
The few details that we were given about his youth were contradictory. Early in his career with Five-0, he was wounded and held hostage by a soldier suffering from a mental breakdown. A television reporter at the scene told his audience that Williams was a ‘local’ boy, born and educated in Hawaii and that he went to the University of Hawaii for one year, majoring in psychology, before transferring to Berkeley to study police science. However, years later, Dan encountered an old girlfriend who he supposedly knew while he was a student at O’Farrell High School in California. According to Melissa (the girlfriend), he kissed her for the first time on the roof of her parents’ house, and their romance ended when he went away to Berkeley.
We do know that one of his hobbies, in his younger days, was making jewelry from soft metals. He was not terribly good at it, and decided to find another hobby. We were not told what the new hobby was.
We know that Dan did time in the service (in one episode, he was shown a gun and said that it was his, but that he had not fired it since he got out of the service). Though we were not told which branch of the service he was in, McGarrett had no qualms about sending him undercover as a navy medic, so we might conclude that this was how he did his national service.
When we first met him Dan was a smoker, but it appears that he kicked the habit, perhaps under the influence of McGarrett, who was a devout non-smoker. He was seen drinking in several episodes, and was once heard ordering bourbon. He lived alone (his apartment was remarkably clean and tidy for a bachelor – did he have a cleaning lady?), though he was very attractive to women, and as the series progressed, gained something of a reputation as a womanizer. (In one episode, McGarrett warned him about mixing business with pleasure.)
After eleven years as McGarrett’s second-in-command, Williams disappeared from the unit without explanation.
In the absence of any official explanation, fans have concocted their own theories, which vary wildly.
In view of the fact that McGarrett never mentioned his name again, some have supposed that whatever the reason for his departure, it was very damaging to his relationship with his boss. Some of the scenarios put forward are that he had a serious disagreement with McGarrett, and walked out, or that, after years of suffering incredible stress and trauma in the line of duty, he had a nervous breakdown. Perhaps the simple explanation is that, after eleven years, he got tired of being second banana, and, realizing that McGarrett was never going to let go of the top job, quit.
Williams later briefly appeared in the 1997 Five-O remake's unaired pilot, where he had moved on to now become the governor of Hawaii. McGarrett is absent from the episode altogether, perhaps suggesting that he had now retired.