Koshy co-created, produced and starred as the title character in the YouTube Premium comedy series Liza on Demand (2018–2021), which earned her several accolades, and hosted the Nickelodeon game show revival Double Dare (2018–2019), for which she received a Daytime Emmy Award nomination.

[12] In 2014, after attending Lamar High School,[13] Koshy enrolled in the University of Houston and began to study business marketing.

[19] In November 2016, just before the 2016 election, Koshy interviewed President Barack Obama on her YouTube channel to encourage voter registration.

[18][20] Koshy's videos feature "her loud facial expressions, quick pace, and her commitment to looking as ridiculous as possible as the joke demands.

"[21] She suspended adding new videos to her main YouTube account in early 2018 as she turned to full-time acting and hosting work.

[36][37] Koshy stars in and co-produces a YouTube Premium situation comedy series, Liza on Demand, which premiered in June 2018, "following the chaotic misadventures of the eponymous character" as she works to become an "elite tasker"[38] doing odd jobs for pay.

A review in The New York Times stated: "Both Koshy and [Jordan] Fisher are accomplished professional dancers, and the movie doesn't skimp on showcasing their gifts.

[32] She also hosted Nigel Lythgoe's series Every Single Step and was "the only social entertainer chosen to promote the 2016 MTV Movie Awards.

[55] Koshy collaborates with The Giving Keys, a jewelry company that employs and supports the formerly homeless population, on a necklace collection.

[6] The Washington Post cited Koshy as one of the "funny women...at the top of their game today [who] girls get to study" as models for comedy and empowerment.

[69] John Jurgensen of The Wall Street Journal described Koshy's appeal as follows: "Her comedy is heavy on self-deprecation, slapstick and wordplay, more goofy than snarky.

... One reason her sketches work for advertisers is the replay factor, [squeezing] in dozens of puns and double meanings, in part to encourage easily distracted viewers to re-watch.

... Koshy has proven to be safe territory for established entertainment companies and advertisers who have fled from edgier online content".

[11] Alexis Gunderson of Paste compared Koshy to Lucille Ball and calls her a "physical comedy wunderkind" and "a tiny magnetic goofball".