Marley is a shy, unambitious wallflower who is the daughter of McKinley High's cafeteria lady, and aspires to be a singer on radio rather than on Broadway.

Marley is introduced as the shy wallflower with a hidden passion for singing, the daughter of cafeteria lady Millie Rose.

However, when Marley discovers that Jake is dating Kitty Wilde, a cheerleader that bullied her and said awful things about her mother's obesity, she is devastated.

When Jake and Kitty break up, it is around the time that Finn announces a musical performance of Grease, which undergoes budget cuts leading to difficulties in funding.

When auditioning, Marley meets Ryder Lynn, a football player and transfer student whom she grows briefly attracted to.

[2] Marley gets the role of Sandy and Unique gets Rizzo but is forced to surrender the part to Santana Lopez after Sue exploits bullying from her peers to her parents.

After the musical, which Rachel leaves New York to attend to show support for Finn, Marley develops bulimia and skips lunches after losing confidence in her body.

In this season, she gets into a skirmish with a Cheerio named Bree, who is tasked by Sue Sylvester, who has returned to McKinley High and demoted Principal Figgins to the role of janitor, to take down the Glee Club and promoted to Cheerio captain, despite having drenched Tina Cohen-Chang during her senior prom when she wins prom queen.

[11] Marley finds out that Jake had been cheating on her with Bree and as a result, she breaks up with him, despite his numerous apologies and attempts to win her back.

She puts her love life to the side to focus on her songwriting career but is unsuccessful at getting anyone to accept her music, later revealing to Ryder her intentions to quit the New Directions.

[13] Things take a turn for the worse when the New Directions loses Nationals, giving Sue Sylvester the excuse she needed to disband Glee Club.

She appears in Jagged Little Tapestry through the use of archival footage, seen sitting behind Blaine Anderson during a mashup of Will You Love Me Tomorrow and Head Over Feet.

Some fans have also expressed disappointment in Lea Michele and Melissa Benoist not sharing a scene together despite Marley's first song being a duet with Rachel Berry.

In The Role You Were Born to Play, the decision to use "Blow Me (One Last Kiss)" by P!nk was criticized by Karen Walsh of Entertainment Weekly as being a poor choice for an audition song but nevertheless, insisted that she "dug the harmonies on this, and the word changes.

"[24] Natalie Fisher of Hypable described Benoist's duet with Becca Tobin in a rendition of Bonnie Tyler's "Holding Out for a Hero" as having "more lesbian sexual tension than anything in the entire Brittana plot line.

"[25] Michael Slezak of TV Line praised Benoist's duet with Cory Monteith on "Don't Dream It's Over" which later developed into a group performance, writing, "What an absolutely gorgeous choice…someone ought to sagely scoop this one up on The Voice or The X Factor".

[26] Erin Strecker of Entertainment Weekly gave Benoist's duet with Heather Morris, a rendition of "Tell Him" by the Exciters, a B+, writing, "it wasn’t the strongest of the night, but it was a fun couple of minutes".

[27] Sandra Gonzalez gave Benoist's rendition of "Superstition" by Stevie Wonder alongside Amber Riley and Darren Criss an A−, writing, "Marley gets in touch with her inner diva, thanks to some help (and killer riffs) from Mercedes.

A majority of fans who were in support of Rachel Berry took to express discomfort towards casting a replacement while some were disappointed that she was not living up to expectations.