Native to the planet Kenda II, Quaice served on various planets and starbases during his long career in Starfleet. He was married to his wife, Patricia, for many years and became Beverly Crusher's mentor during her internship on planet Delos IV in 2352, during which time they became good friends.
After his wife's death in 2367, Commander Quaice decided to retire and return to Kenda II. He was still in good spirits, but was somewhat depressed with the prospect of living the rest of his life and having to say goodbye to lifelong friends. Apparently, the two friends had kept in touch over the years and when she discovered his plans to return home, Doctor Crusher took the opportunity to arrange for him to granted passage on the Enterprise as the ship would be visiting the Starbase were Dr. Quaice was assigned. He was picked up by the USS Enterprise-D during a crew rotation and ferried home soon afterward. Dr Crusher greeted her friend in the transporter room and they embraced briefly. As the two walked along the corridor, they chatted briefly wherein the conversation turned to the recent death of Dr Quaice's wife and his subsequent depression. The two arranged to meet for breakfast the following day. While Quaice was on board, a warp bubble experiment run by Wesley Crusher trapped Dr. Crusher in an alternate reality where everything and everyone began disappearing, with only Crusher noticing the changes. Quaice was the first to vanish in this reality.
"It's good to see you again, Beverly."
"You look wonderful."
"A lie I can live with."
- - Dalen Quaice and Beverly Crusher
"We had a lifetime together, doing all the things we'd ever dreamed, and more. But when she was gone, I couldn't continue to work in that office, sleep in that bed without her. The absence of her was too distracting."
- - Dalen Quaice, of his wife's death
"You know what the worst part of growing old is? So many of the people you've known all your life are gone and you realize you didn't take the time to appreciate them while you still could."
- - Dalen Quaice
Dalen Quaice was played by actor Bill Erwin.
In the alternate timeline of the Star Trek: Myriad Universes short story "Brave New World", Doctor Quaice takes advantage of Doctor Ira Graves' technological advance which allows a person to transfer their consciousness into an android body. He creates a body based upon his appearance as a youngeman, going on to serve as chief medical officer on the USS Enterprise-D following Doctor Crusher's transfer to Starfleet Medical. Quaice serves in this position until at least 2378.