The second act explores family dynamics that evolve as he and his ex-wife plan his son's bar mitzvah, which is complicated as Whizzer comes down with an early case of AIDS.

Composer William Finn began his theater career with a one-act musical In Trousers (1979), which centers on the character Marvin questioning his sexuality.

[4] Finn soon wrote the songs for another one-act musical about Marvin and his family, March of the Falsettos, collaborating with director James Lapine on the book.

[11] In writing both acts of Falsettos, Finn prioritized making the audience laugh, believing that provoking laughter is more challenging than garnering tears.

[13] Some songs, including "Four Jews in a Room Bitching", originated with Finn humming improvised melodies while strolling the streets of New York City.

[13] In 1979 in New York City, Marvin, his ten-year-old son Jason, his psychiatrist Mendel, and his boyfriend Whizzer are in the midst of an argument ("Four Jews In a Room Bitching").

Jason is very worried that because of Marvin's sexuality, he will turn out to be gay too ("'My Father's a Homo"), and his parents suggest he receive therapy from Mendel to calm his mood swings.

Nancy Reagan is in the White House, and two new people are introduced: Marvin's lesbian neighbors Dr. Charlotte, an internist, and Cordelia, a non-Jewish caterer specializing in Jewish cuisine.

Dr. Charlotte, meanwhile, is becoming aware that young gay men in the city arrive at the hospital sick with a mysterious illness that no one understands ("Something Bad is Happening").

† - Indicates a song not included on the cast album Falsettos opened on Broadway at the John Golden Theatre on April 29, 1992, and closed on June 27, 1993, after 487 performances.

[20] The cast and producers were unsure if the show would find a strong following on Broadway, but were encouraged when Frank Rich of The New York Times gave the musical a positive review.

Hoping to create an easily-identifiable logo inspired by the minimalist design of Cats, the Weisslers used the work of artist Keith Haring in which two adults and a child hold up a bright red heart.

"[21] The advertisers invited the newly-crowned Miss America, who had recently launched an Atlantic City-based AIDS awareness campaign, to attend the show and be photographed.

[21] In 1994, Sydney Theatre Company presented an Australian production directed by Wayne Harrison and featuring John O'May as Marvin, Gina Riley as Trina, Tony Sheldon as Mendel, and Simon Burke as Whizzer.

The cast featured Tamlyn Henderson as Marvin, Katrina Retallick as Trina, Stephen Anderson as Mendel, Ben Hall as Whizzer, Elise McCann as Cordelia and Margi de Ferranti as Charlotte.

[39] The original cast featured Natasha J Barnes as Cordelia, Daniel Boys as Marvin, Gemma Knight-Jones as Charlotte, Laura Pitt-Pulford as Trina, and Oliver Savile as Whizzer.

"[53] Trina's struggles with the men in her life are also symbolized in "I'm Breaking Down", where she manically chops bananas and carrots for her "banana-carrot surprise", "an unusual combination but an appropriately phallic one".

"[13] Critics interpreted the set design of the 2016 revival to reflect immaturity by representing the New York City skyline in the form of children's building blocks.

[28] Frank Rich of The New York Times praised the 1992 opening night performance as "exhilarating and heartbreaking", speaking favorably of the musical's cast, humor, and emotional depth.

[47] He called Jason's bar mitzvah scene "one of the most moving you've ever seen" and explained that in addressing the AIDS epidemic, "It is the heaven-sent gift of Mr. Finn and company that they make you believe that the love, no less fortissimo, somehow lingers on.

[54] Gerard thought "Four Jews in a Room Bitching" "hilarious" and praised the musical's pacing, opining that "Lapine and Finn tell their complex story with astonishing economy".

[54] In her report about Finn's Tony Award acceptance speech in June 1992, Kim Hubbard of People characterized Falsettos as both "a laugh-a-minute musical" and "a tragedy filled with hope".

[28] John Simon of New York magazine, however, lamented the musical's "big lie" of portraying the illness of AIDS to look "gentle, elegant–something like a nineteenth-century heroine's wistful expiring of consumption–where we all know that it is grueling and gruesome".

[56] Douglas Watt of the New York Daily News described the musical as "too sweet and sugary by far" and its plot as "sticky with sentiment", comparing the tone of Falsettos to that of a soap opera.

"[56] Reviewing the 2016 revival, Alexis Soloski of The Guardian called the show "radically intimate" and praised the musical's emotional depth and character development, remarking that, "anyone who leaves without shedding a tear may want to see his or her ophthalmologist".

[58] Chris Jones of the Chicago Tribune wrote that Falsettos "throbs with passion and compassion, a masterwork strong enough to bare [sic] formative comparison to the work of Stephen Sondheim, but a whole lot more cuddly of a show".

[59] He praised the performances of Block, Thoms, and Wolfe, writing, "The show centers on men in its structure, but the women in this cast all are so strong that you sense a realignment from 25 years ago.

"[60] Linda Winer of Newsweek appreciated Finn's "enormously quotable, conversational lyrics that catch in the throat as often as they stick in the mind", describing "Unlikely Lovers" as an "emotional killer of an anthem".

[62] Christopher Kelly of NJ.com praised Rannells and Block, stating that the latter's performance of "I'm Breaking Down" "sends the show to such dizzying heights that it takes the audience a few minutes to recover".

"[63] Melissa Rose Bernardo of Entertainment Weekly gave the show a "B+" and noted the musical's emotional impact, exclaiming, "Curse you, William Finn, for writing these heart-wrenching songs.