He rose to fame starring on the television series Glee (2010–2015) and received Emmy and Golden Globe acting awards for his leading role as spree killer Andrew Cunanan in The Assassination of Gianni Versace: American Crime Story (2018).

In 2015, Criss co-founded Elsie Fest which is touted as "New York City's first outdoor music festival celebrating tunes from the stage and screen".

[7] Criss was raised primarily in San Francisco, apart from 1988 to 1992, when the family resided in Honolulu, Hawaii, where his father started EastWest Bank, serving as chairman and CEO.

[9] In 2009, Criss obtained his Bachelor of Fine Arts from the University of Michigan, majoring in Theater Performance and minoring in Musicology and Italian.

[9][10] Criss' interest in music started in early childhood; at age five, he began taking violin lessons and was classically trained for the next fifteen years.

[14][15] When he was fifteen, Criss began learning music composition and wrote his first song, which he later used as the title track of his first EP Human, released in 2009.

[17] At St Ignatius, he was a member of the performing arts program and acted in work, including, The Music Man, The Diary of Anne Frank,[18] and Fiddler on the Roof.

[22] Criss made his professional stage debut at the age of ten as Cesario in 42nd Street Moon's production of Fanny (1997), then played Mauro in the Richard Rodgers and Stephen Sondheim musical Do I Hear a Waltz?

[23][24][25] Throughout his adolescence, Criss appeared in a number of the American Conservatory Theater's plays, notably A Christmas Carol, A Midsummer Night's Dream, and The Voysey Inheritance.

[29] Upon receiving his Bachelor of Fine Arts in 2009, Criss, along with some friends and classmates from the University of Michigan, co-founded StarKid Productions, a musical theater company.

[40] Both Billboard's Jillian Mapes and Erica Futterman of Rolling Stone deemed "Teenage Dream" the best song of "Never Been Kissed", the episode in which it featured.

[44] A Billboard cover-feature on Criss noted that the performance "arguably ushered in the trend of more current pop hits being reworked by the [Glee] cast.

[49] Blaine initially served as a friend and mentor for Kurt, the bullied gay member of the Warblers' rival glee club, New Directions.

Chemistry between the two characters, combined with fan support for the potential couple, led series co-creator Ryan Murphy to pair them romantically onscreen.

At the beginning of the third season, Blaine transfers to McKinley High and joins New Directions; concurrently, Criss was promoted from recurring guest star to the show's main cast.

Discussing public response to his character, Criss stated that he particularly enjoyed comments from "people from parts of the world who are maybe not as exposed to certain ideologies", but had reconsidered their stance on relationships and human rights as a result of the Blaine and Kurt storyline.

He called this response "phenomenal" and said, "I was a straight kid growing up in a very gay community and it's something that I've had to watch so many friends have to struggle with and have no place to go to identify in kind of a grander media culture.

[62][63] In January 2012, Criss made his Broadway debut, replacing Daniel Radcliffe in the role of J. Pierrepont Finch in the revival of How to Succeed in Business Without Really Trying for a three-week engagement at the Al Hirschfeld Theatre.

[68] During a benefit concert for public school arts on April 14, 2013, Criss was made an honorary member of Yale University's a cappella singing group The Whiffenpoofs.

Criss worked with previous collaborators Matt and Nick Lang of Team StarKid, who co-wrote the series as well as executive produce.

[92][93] From April 14 to July 10, 2022, he performed in the Broadway revival of David Mamet's American Buffalo alongside Sam Rockwell and Laurence Fishburne.

[97] Criss has appeared on the magazine covers of Billboard,[98] Entertainment Weekly,[99] Out,[100] Playbill,[101] TV Guide,[102] Da Man,[103] GT,[104] Prestige,[105] and Essential Homme.

[113] Criss is an advocate for LGBT rights and is an active supporter of The Trevor Project, the leading national organization focused on suicide prevention efforts among lesbian, gay, bisexual, transgender, queer, and questioning (LGBTQ) youth.

It was part of the compilation album Chimes of Freedom: Songs of Bob Dylan Honoring 50 Years of Amnesty International, released on January 24, 2012.

[118] Criss has performed at various charity benefits including American Conservatory Theater, AIDS Project Los Angeles, New Conservatory Theatre Center, Toys for Tots, City of Hope National Medical Center, Motion Picture & Television Fund, Public School Arts, MusiCares Foundation, The Old Vic, UCLA's Jonsson Comprehensive Cancer Center, Big Brothers Big Sisters of America, Young Storytellers Foundation, and the Elizabeth Glaser Pediatric AIDS Foundation.