When auditioning for the part of the holographic doctor, Robert Picardo was asked to say the line "Somebody forgot to turn off my program." He did so, then ad-libbed "I'm a doctor, not a light bulb" and got the part.
The character of Ensign Samantha Wildman was named after a little girl who died tragically in an accident. The girl's organs were donated to save the life of the wife of episode writer Jimmy Diggs. The real Samantha loved animals, so Ensign Wildman was written as the head of Voyager's Xenobiology Department.
Jeri Ryan has stated that she would become sick with anxiety at the thought of performing scenes with Kate Mulgrew. Most cast members have affirmed that their working relationship was quite strained during the first years of their cooperation. Mulgrew later admitted that she wanted to de-sexualize Star Trek in general and her Janeway character in particular (e.g. resisting attempts to have her engage in a relationship with a male crew member), so she disapproved when an obviously sexualized character like Seven was made the new center of attention. Mulgrew later took full responsibility for the bad relationship and apologized to Ryan, commenting that she "did a marvelous job in a very difficult role." They have since appeared on many Star Trek conventions together and apparently buried the hatchet.
Garrett Wang does not actually play the clarinet. But anytime Harry Kim plays it, Wang chose (on his own) to learn the correct finger placements to match the music playing in the professional recording he was following, making the illusion more convincing.
According to Garrett Wang (who played Harry Kim), the first episode of Star Trek: The Next Generation (1987) that he saw was Code of Honor (1987) which is widely considered one of the worst episodes of that series. Every time Wang tried to give the series another chance, it was a rerun of "Code of Honor." Because Wang was not a fan of that series, he feels that he was more relaxed during his audition for this series. After he was cast, the producers gave him episodes of The Next Generation to prepare for his role. The first episode they gave him was "Code of Honor."