[23] Takei subsequently appeared alongside such actors as Frank Sinatra in Never So Few (uncredited, 1959), Richard Burton in Ice Palace, Jeffrey Hunter in Hell to Eternity (1960), Alec Guinness in A Majority of One (1961), James Caan in Red Line 7000 (1965), and Cary Grant in Walk, Don't Run (1966).

[27] In 1965, producer Gene Roddenberry cast Takei as astrosciences physicist Sulu in the second pilot for the original Star Trek television series.

[28] Takei admitted in an interview that he initially felt threatened by Koenig's presence, but later grew to be friends with him as the image of the officers sharing the ship's helm panel side-by-side became iconic.

In the summer of 2007, Takei played Sulu in the fan-made Internet based series Star Trek New Voyages: Phase II episode "World Enough and Time".

At one point, he had hoped to make a film or telefilm based on chapters dealing with the internment of Japanese-Americans during World War II, of which he had personal experience.

In 2010, Takei recorded a series of public service announcements for the Social Security Administration to help promote applying online for benefits.

[35] In 2011, he appeared with husband Brad Altman in All Star Mr & Mrs, a show on ITV in Britain presented by Phillip Schofield and Fern Britton.

[37] Takei was featured with Martin Sheen and Jamie Lee Curtis in a performance of Dustin Lance Black's play 8—a staged reenactment of the federal trial Perry v. Brown that overturned California's Proposition 8 ban on same-sex marriage—as William Tam.

The show is based on Takei's own experiences and research into the Japanese American internment of World War II and premiered at the Old Globe Theatre in Balboa Park in San Diego, California.

[42] The Guardian said it was "unexceptional though often affecting"; Deadline called it "a triumph of a rare sort, shedding light in a dark corner of our history with uncommon generosity of spirit".

[55] In 2019, Takei published They Called Us Enemy, a 208-page memoir in the form of a graphic novel, with a particular focus on his family's time in internment, co-written with Justin Eisinger and Steven Scott and illustrated by Harmony Becker.

Gen. Linell Letendre announced that They Called Us Enemy, which details both Takei's struggle with internment and understanding of American democracy, would be part of the Academy's new reading initiative for cadets.

[59] In October 2005, Takei revealed in an issue of Frontiers magazine that he is gay and had been in a committed relationship with his partner, Brad Altman, for 18 years; the move was prompted by then California governor Arnold Schwarzenegger's veto of same-sex marriage legislation.

[62] In an on-air telephone interview with Howard Stern in December 2005, Takei explained, "[We (gay people)] are masculine, we are feminine, we are caring, we are abusive.

[74] On June 17, shortly after Takei and Altman obtained their marriage license, they spread the news by holding a press conference outside the West Hollywood city auditorium.

[75] They were married on September 14, 2008, at the Democracy Forum of the Japanese American National Museum in Los Angeles, of which Takei is one of the founders and serves as a member of its board of trustees.

[77] Takei and Altman appeared in a celebrity edition of The Newlywed Game TV show, which the GSN cable network aired October 13, 2009.

[79] In February 2010, Takei and Altman became the second same-sex couple to appear on the British game show All Star Mr & Mrs, losing to rugby player Phil Vickery and his wife Kate.

During the campaign, Takei's bid for the city council caused one local station to stop running the repeats of the original Star Trek series until after the election and KNBC-TV to substitute the premiere episode of the Star Trek animated series scheduled by the network with another in which his character did not appear, in attempts to avoid violating the FCC's equal-time rule.

Takei was called away from the set of Star Trek: The Motion Picture in 1978 to cast the tie-breaking vote for the creation of the Los Angeles subway system.

Takei's video was made as a response to McCance making blatantly homophobic remarks, stating that he "enjoys the fact that [gay people] give each other AIDS and die".

In May 2011, in response to a Tennessee State Legislature bill that prohibited school teachers or students from using any language that alludes to the existence of homosexuality, Takei released another PSA in which he offered up his name, suggesting that people could just substitute that for 'gay'.

[91][92] Takei described Higbie's comments as "dangerous"[93] and went on to say on The Last Word with Lawrence O'Donnell that "[r]egistration of any group of people, and certainly registration of Muslims, is a prelude to internment.

[95] A few hours later, he acknowledged that it had all been an April Fools' joke and instead announced his support for Jon Ossoff, who was running in Georgia's 6th congressional district special election, 2017.

Takei formerly served as chair of the Council of Governors of East West Players, one of the pioneering Asian Pacific American theaters in the United States, until 2018.

[98] That same year, he played the parts of Sam Kimura and Ojii-San in East West Players' and the Japanese American Cultural & Community Center's joint production of Allegiance.

[99] Takei and his husband Brad Altman own a New York City-based digital publication called Second Nexus which publishes "news with commentary from a progressive perspective".

[107][108] In September 2013, Takei used his Facebook page to defend Nina Davuluri, who was targeted by a backlash of racist and xenophobic comments after being named Miss America 2014.

[111] However, Takei also attracted criticism from some people with disabilities in 2014 for his posting of a meme on Facebook and Twitter which shows a wheelchair-using woman standing up to reach something from the top shelf in a store and is captioned "there has been a miracle in the alcohol isle" [sic].

[121] In 2004, the government of Japan conferred upon Takei the Order of the Rising Sun, Gold Rays with Rosette, which represents the fourth highest of six classes associated with the award.