(written from a Production point of view)
Rosalind Chao (born 23 September 1957; age 63) is an actress best known for her portrayal of Keiko O'Brien (née Ishikawa) in Star Trek: The Next Generation and Star Trek: Deep Space Nine. (While the character of Keiko is a Japanese national, the actress Chao is Chinese-American.) Chao appeared in eight episodes of Next Generation and nineteen episodes of Deep Space Nine.
Chao has remained friends with Colm Meaney and attended his wedding in Beverly Hills on March 15, 2007. At Grand Slam XV, Meaney said "It was lovely having my TV wife at my wedding".  Chao herself is married to actor and fellow TNG guest star Simon Templeman.
Before being cast as Keiko in the episode "Data's Day", she originally auditioned and was considered for the role of Natasha Yar, according to a 1987 studio memo.  Her costume from "Data's Day" was later sold off on the web. 
Her first credited role was in a 1970 episode of Lucille Ball's series, Here's Lucy, entitled "Lucy the Laundress". Her first major acting role was in the 1972 television series Anna and the King, in which she played Princess Serena. She played Soon-Lee Klinger in the penultimate and final episodes of M*A*S*H with David Ogden Stiers. She reprised the role in the short-lived spinoff, AfterMASH.
Chao also had recurring roles on other popular series, such as Diff'rent Strokes, in which she played Miss Chung, and Falcon Crest in which she played Li Ying. More recently, she has had recurring roles on 10-8: Officers on Duty, Six Feet Under, and The O.C.
In 1987, she appeared in the series Max Headroom, along with Matt Frewer, Concetta Tomei, George Coe, Andreas Katsulas, W. Morgan Sheppard, and the late Charles Rocket. In 2001, she played a midwife in a pivotal episode of Once and Again (with Billy Campbell and Paul Dooley.) In 2003 she appeared on an episode of Monk, alongside Jamie McShane and Michael Reisz; the show also featured Stanley Kamel in a recurring role as the title character's psychiatrist, though he did not appear in the episode with Chao; Chao's husband, Simon Templeman, likewise appeared in an episode during the same season.
Chao has also made appearances in many successful films, including The Joy Luck Club (co-starring Tamlyn Tomita and France Nuyen), What Dreams May Come (featuring Scott Trimble), I Am Sam (which also featured her TNG co-star Brent Spiner), and Freaky Friday  (featuring Willie Garson). Chao also co-starred in the 1998 fantasy film What Dreams May Come based upon the novel by TOS scribe Richard Matheson.
In 2005, she starred in Just Like Heaven (with fellow TNG and DS9 guest star Ron Canada) and in Life of the Party (with VOY guest star David Clennon). Recently, she has made guest appearances on the HBO drama series Tell Me You Love Me. Ronny Cox has also appeared on that series.
As of 2015, she has a recurring role on the television show Sin City Saints as Mrs. Wu. In 2016, she appeared in an episode of Hawaii Five-0 (starring Daniel Dae Kim and developed by Roberto Orci and Alex Kurtzman), portraying another character named Keiko, the governor of Hawaii Keiko Mahoe.
Star Trek appearances
- "A Man Alone" (Season 1)
- "If Wishes Were Horses"
- "In the Hands of the Prophets"
- "The Siege" (Season 2)
- "Armageddon Game"
- "The House of Quark" (Season 3)
- "Accession" (Season 4)
- "Hard Time"
- "Body Parts"
- "Looking for par'Mach in All the Wrong Places" (Season 5)
- "The Assignment"
- "The Begotten"
- "Time's Orphan" (Season 6)
- "What You Leave Behind" (Season 7)