The TV star, 68, decided to publicly disclose his sexuality after taking on the role as "turbulently frustrated" psychologist MARTIN DYSART in the Los Angeles stage production of Equus.
Takei tells gay and lesbian magazine Frontiers, "The world has changed from when I was a young teen feeling ashamed for being gay.
"The issue of gay marriage is now a political issue. That would have been unthinkable when I was young."
The actor, who played HIKARU SULU since Star Trek began in 1966, has been with his partner BRAD ALTMAN for 18 years.
Japanese-American Takei admits he was ashamed of his ethnic background and sexuality during his teen years.
Speaking of racism and homophobic behaviour, he says, "It's against basic decency and what American values stand for."