2012–2016: I'd Cap That, computer engineering, and Vine

Ko shortened his professional surname from Kolodziejzyk early in his career,^[6] as his Polish surname was too difficult to spell and pronounce.^[2] In March 2012, he began to develop the photo-sharing mobile app I'd Cap That, which automatically added meme-like captions to images. It went viral and was the App Store's Free iOS App Of The Week in May, amassing over four million users in four months. Ko wanted to join a startup and continue developing apps.^[7][8] I'd Cap That was acquired several months later by a startup called Iddiction, and Ko worked there on the app for two years before quitting in 2014.^[9][10] He also moved to San Francisco.^[11]

Ko first began uploading to Vine, a six-second video platform, in 2013. He partnered with the now-defunct multi-channel network Fullscreen, with Mahzad Babayan becoming his full-time talent manager.^{[lower-alpha 4]} He credited the network and his background in computer engineering for his early success.^[13] In May 2014, Ko and his friend Devon Townsend left on an eight-month backpacking trip in southeast Asia. Throughout the trip, the pair created Vines and started several side projects for ad revenue and experience creating apps with other technologies such as Node.js. The videos were unexpectedly viral and Ko became a popular figure on Vine.^[9][14] He had amassed over 290,000 followers by July.^[15]

In January 2015, the two returned to the United States. Moving to Los Angeles, they looked for software jobs and continued to make Vines.^[9] Ko collaborated with comedian Hannibal Buress to promote Buress' Comedy Central show Why? with Hannibal Buress (2015). By November 2015, he had almost two million followers on the platform.^[16]

Ko worked for the company Victorious for eight months and had less time to create content. He also frequently had to leave midday for auditions. His manager gave him a job as a senior iOS developer at her employer Fullscreen, where they would be more relaxed about him leaving midday for content creation as a social media company. Ko contributed to the code for Fullscreen's subscription service. At Fullscreen, Ko also met Noel Miller, a web designer from marketing and fellow Viner, by chance after they had previously talked online. The pair became close and often created internet content on their lunch breaks.^[9][11]

In June 2016, Ko starred in the Vine-produced series Camp Unplug alongside twelve other Viners.^[17] He quit his job at Fullscreen the next month, deciding that he could support himself on sponsorships alone.^[9]

2016–2019: YouTube commentary, music, and podcasts

Ko joined YouTube on 30 May 2014.^[18] After Vine was discontinued, he shifted to YouTube content. He and Miller became popular on YouTube with their series That's Cringe, hosted on Ko's channel, where the two react to content they consider dumb. That's Cringe has over 153 million combined views and makes up most of his channel's most popular videos.^[14][19] An episode on controversial YouTuber Jake Paul in October 2017 amassed over seventeen million views.^[20] Another episode on the Christian lifestyle channel Girl Defined spurred viral TikTok memes mocking Girl Defined and their videos' themes of extended chastity.^[21]

Ko's other content focuses on internet culture, such as criticism of internet personalities, NFTs or ASMR videos involving dangerous acts. He and other commentary YouTubers have been described as "media critics" for an online millennial audience.^[19][22] Vulture said that his videos helped bring attention to YouTube commentary and help it grow from a subsection of reaction videos.^[20] Ko is also part of the cast of Jimmy Tatro's web series The Real Bros of Simi Valley, which airs on Facebook Watch.^[14] He used to edit his videos himself, but began to hire outside editors and a production team.^[11]

Ko and Miller have made satirical rap songs together as Tiny Meat Gang (TMG) since 2017.^[23] Miller dubbed the pair "Tiny Meat Gang" after joking about "the weird idea of an 'unborn child as an fboy [sic]' posing in a sonogram".^[11][12] However, the two began considering music earnestly after they were contacted by producer Diamond Pistols^[24] and released their first extended play Bangers & Ass the same year.^[25] After struggling with repeated demonetization, Ko and Miller began the Tiny Meat Gang Podcast in October 2017 to make up for losses. The podcast is funded solely by their Patreon supporters, with each hour-long episode discussing various topics related to pop and internet culture.^[9][26][23] Ko also hosts the podcast Insanely Chill.^[27]

In 2018, Ko and Miller went on tour and reached 1 million subscribers on his main channel in June. In an interview with Tubefilter, Ko attributed his success to "ripping on the Paul brothers."^[27] The same year, Post Malone was featured in an episode of their podcast^[23] and Tiny Meat Gang released their second EP, Locals Only.^[25]

2019–2021: Tiny Meat Gang and continued growth

In early 2019, Tiny Meat Gang won Best Podcast at the 11th Shorty Awards.^[26][28] Ko and Miller also appeared in a sold-out live comedy tour across the United States as Tiny Meat Gang.^[25]

After Jake Paul released a vlog confronting Ko, who he called a 'cyberbully', in person on Jeff Wittek's podcast, Paul was widely criticized online and the video received over 800,000 dislikes.^[20][29] The Washington Post described it as an example of celebrities dismissing genuine criticism as hate.^[30] However, Ko gained around 140,000 subscribers directly after the incident and surpassed four million by late 2019.^[31][32]

Tiny Meat Gang collaborated with Blackbear for the single "short kings anthem".^[23] In October, they signed with Arista Records and announced a new EP.^[25] On 22 November, Ko partnered with Killer Merch to launch a merchandise collection.^[32] Tiny Meat Gang rescheduled their next tour to the second half of 2020.^[23]

In October 2020, Ko hosted an eight-episode podcast on iHeartRadio titled The Pleasure is Ours, with guest stars such as Drew Gooden and Emma Chamberlain, in which they discuss truisms and popular sayings.^[14]

Adlan Jackson of The New York Times Magazine noted that as Ko and Miller rose in popularity, many of the figures they have mocked appeared in their videos.^[19] After criticizing Dhar Mann for his formulaic videos, Ko produced one of his videos and shifted his opinion, saying they were made that way so that his audience, mainly foreigners and children, could understand.^[33] Controversial entrepreneur Gary Vaynerchuk also appeared in a 2021 episode of Tiny Meat Gang. Due to this, some fans began to worry about a potential conflict of interest and that the two "would [be incentivized] to pull their punches."^[19]

2021–present: Tiny Meat Gang Studios

In a June 2021 interview, Ko said he intended to develop a media network from the Tiny Meat Gang Podcast.^[11] He and Miller co-founded Tiny Meat Gang Studios, a comedy podcast network, in October 2021. They are represented by United Talent Agency, who have assisted in TMG Studios' expansion. The company currently has seven podcasts, including the flagship Tiny Meat Gang Podcast and Insanely Chill. The Tiny Meat Gang Podcast is now divided into two one-hour segments, with the first free and the second available only to subscribers.^[12] It had over 200 million downloads in 2022. An October 2022 episode featuring the YouTuber MrBeast became one of the most-viewed episodes of the podcast.^[34][35]