That same year, he was included on XXL magazine's 2020 Freshman Class[2] and released his debut studio album Thats What They All Say (2020), which received platinum certification by the Recording Industry Association of America (RIAA).

[2] He made his acting debut as Jeremy in the 2023 remake of the 1992 film White Men Can't Jump, directed by Calmatic.

[6][11] Throughout high school, he often played sold-out shows at Louisville venues like Mercury Ballroom, Headliners, and the Haymarket Whiskey Bar.

[12] In June 2016, less than a month after graduating from Atherton High School, he released the mixtape 18, which was the first album on his label and music collective, Private Garden.

[13][14] The collective also features Harlow's frequent collaborators, the Homies, composed of Louisville rappers and producers Ace Pro, 2forWoyne, Shloob, Quiiso, and Ronnie Lucciano.

On September 19, 2019, Harlow released the single "Heavy Hitter," a tribute to Louisville attorney and internet personality Darryl Isaacs.

[36] The song was widely shared on the TikTok social media platform,[37] and the Cole Bennett-produced video has surpassed 135 million views as of May 2021.

On June 24, 2020, Harlow released the remix of "Whats Poppin", which features DaBaby, Tory Lanez, and Lil Wayne.

[52] The song performed well on the Hot 100 with a number 18 debut and peak and also received praise from Kanye West,[53] who previously was involved in the production of "Industry Baby".

[56] On September 3, 2022, Harlow was the College GameDay guest picker and performer for Ohio State's 2022 season opener, a 21–10 win over Notre Dame.

[57] On April 26, 2023, Harlow took to his social media accounts to announce his third album, Jackman, along with its release date and reveal its cover art.

SZA and Harlow co-headlined the festival, which was to "feature 26 acts on two stages and highlight some of Louisville's local food and culture".

[65] In March 2022, it was announced that Harlow would make his acting debut in a remake of the 1992 film White Men Can't Jump directed by Calmatic.

[66] In April 2023, Harlow joined the cast of the Apple TV+ film The Instigators, co-starring alongside Matt Damon and Casey Affleck.

[67] Harlow's craft has been characterized by critics as blending playful confidence with emotional sincerity in both his music and lyrics,[68][69] which often explore themes such as sexuality, partying, and drug use.

[72][73] In 2020, Kate Hutchinson of The Guardian opined that Harlow's most interesting songs are his more introspective ones, dealing with topics such as being uncomfortable with his acclaim, and his white privilege.

[72] Thomas Hobbs, another writer for The Guardian, wrote that Harlow embraces "being a dorky outsider", while additionally having "enough charisma" to pull off "using language that is usually cringeworthy coming from suburban white people".

[2] Harlow cites a range of influences across multiple genres, including Eminem,[77] Drake, Kanye West, Lil Wayne, Outkast, Paul Wall, Willie Nelson, Johnny Cash, Hall & Oates, Fergie, and Jesse McCartney, among others.

[81] Harlow supports the Black Lives Matter political movement, having attended a rally to protest the killing of Breonna Taylor, which occurred in his hometown.

[83] In October 2021, Harlow donated to five Louisville-based organizations: AMPED, the Center for Women and Families, the Grace M. James Academy of Excellence, Louisville Urban League and Metro United Way.

[84] KFC and Instagram pledged to match up to $50,000 of what Harlow raises through the social media platform's fundraising tool.

Brands to donate a joint $250,000 to the American Red Cross to support those impacted by a deadly tornado in western Kentucky.

[86] In 2023, he founded the Jack Harlow Foundation to “reinvest, uplift and support organizations aiming to make the city that raised him a better place.”[87] That same year, he headlined a rally alongside Kentucky's Democratic governor Andy Beshear ahead of the general election.