After Midnight will air next year after The Late Show with Stephen Colbert, filling a gap left by the exit of James Corden.
Tomlinson, 29, has gained prominence from two Netflix stand-up specials - Quarter Life Crisis and Look at You.
The comic will become the youngest late-night host by more than 20 years.
She joins the likes of NBC's Jimmy Fallon and Seth Meyers, and Jimmy Kimmel at ABC on the late-night circuit and fills the slot left by Corden on The Late Late Show earlier this year.
Tomlinson has gained popularity on social media, particularly TikTok but was also a finalist on NBC's Last Comic Standing in 2015 and was named as one of the top 10 comics to watch by Variety, after appearing at the Just for Laughs festival in 2019.
The format of her new show, After Midnight, will be based on Comedy Central's @midnight With Chris Hardwick, which ran from 2013-2017 and featured a panel of comics.
Production company Funny Or Die, who are behind Brockmire and Billy on the Street, produced the original @midnight and will again return to create this series, with Colbert serving as an executive producer.
He announced After Midnight would be broadcast next year on his show on Wednesday, saying "We'll need someone who is, I don't know, fun, likeable, young, in touch with online trends and available every night of the week."
Colbert shared a screenshot of the moment he told Tomlinson she had got the job, over a Zoom call earlier this week.
Tomlinson, who is currently on a US comedy tour, then joined Colbert on the sofa, joking: "I've never had a real job".
She referenced that she had been "doing stand-up since I was 16, which is not a job".
Tomlinson had a message for people who might not know her, saying: "I'm 29 so if you don't know who I am, don't worry. I barely know myself."
She then said that her 30th birthday is on Saturday and Colbert replied, "Happy birthday, I got you a network show."
Female network comedy television hosts have been hard to come by in the US in recent years, with Lilly Singh's stint as replacement for Carson Daly on NBC being the only notable role in the last few years.
Singh took on his slot from 2019 to 2021, before the show was taken off air.
Comedian Taylor Tomlinson is set to host a new show on the CBS network, making her the only female late-night host in the US.