Julianne Moore is widely regarded as a gay icon and ally who has played various queer roles in movies. Since 1998, she has portrayed at least seven lesbian or bisexual characters, which is more than any other A or B-list star.[1]

Some of her most notable queer roles include Jules in “The Kids Are All Right” (2010), Laurel Hester in “Freeheld” (2015), and Clarissa Vaughan in “The Hours” (2002). She has also starred in other LGBT-themed films such as “Chloe” (2009), “Savage Grace” (2007), and “The End of the Affair” (1999).[1]
Moore has received critical acclaim and awards for her performances, including an Oscar nomination for “The Hours” and a Golden Globe nomination for “The Kids Are All Right”. She has also been praised for her sensitivity and authenticity in portraying complex and diverse queer women.[1]
However, Moore has also faced some criticism and controversy for playing lesbian characters as a straight woman. In 2020, she said that she was not sure if she would play a lesbian character again, acknowledging that representation matters and that people were upset by her role in “The Kids Are All Right”.[2] [4]

“I can see why people were upset,” she said. “We need to give real representation to people, but I’m grateful for all of the experiences that I’ve had as an actor because my job is to communicate a universality of experience to the world.”[2]
Moore has also been a strong supporter and ally of the LGBTQ+ community. She has advocated for marriage equality, transgender rights, and HIV/AIDS awareness. She has also participated in events such as Pride marches, GLAAD Media Awards, and Outfest Film Festival.[3]

References:
[1]7 (All) of Julianne Moore’s Queer Roles Ranked
[2] Julianne Moore On Playing A Lesbian In 2010 Film: ‘I Can See Why People Took Issue’
[3]Julianne Moore: a gay life and career
[4] Julianne Moore says she’s not sure she would play a lesbian today