Daniel L. Kwan was a Starfleet lieutenant junior grade (serial number: SK-105-223). He was promoted to this rank on stardate 46922.6. He was a specialist (grade 5) in warp field dynamics. He had an average efficiency/coind rating of 8.4.
He graduated from Starfleet Academy (Psi Epsilon III) on stardate 40751.5. He was awarded the Jalhal Award for warp field studies, Tezber Award for engineering studies, and D Garza Engineering Scholarship. He was assigned to the USS Pueblo on stardate 44987.6, USS Seaview on stardate 45983.6, and USS Enterprise-D on stardate 46922.6.
Six months after stardate 40987.2, he was serving at the Utopia Planitia Shipyards, Sol system. He was second assistant team leader for the warp engine emergency control systems on stardate 41403.2. He was, also, an assistant team leader on plasma venting and control systems/local installation.
He committed suicide by jumping into a plasma stream on stardate 47622.1. The motivation for Kwan's suicide was initially a mystery to the rest of the crew, as it was not consistent with his personality.
It was later learned that the partially telepathic Kwan had come in contact with a telepathic imprint left since the Enterprise was under construction in 2362, by Lieutenant Walter Pierce, who had caught his lover Marla E. Finn with another man, William Hodges, then killed them both, before committing suicide by jumping into the plasma stream. The imprint caused Kwan to experience a hallucination similar to Pierce's final days, in which Kwan believed he had killed someone (most likely Ensign Calloway), compelling him to take his own life in the same manner that Pierce had.
While investigating Kwan's death, Counselor Deanna Troi was affected by the telepathic imprint as well, and nearly suffered the same fate, before being stopped from jumping by Lieutenant Worf. (TNG: "Eye of the Beholder")