Siddiq's stand-up comedy tends to be in the storytelling style, versus the more common setup/punch-line style. Siddiq's sets involve stories from his personal life, as well his observations on current events, race and politics.

Siddiq's first television appearance was in 2008 on HBO's Def Comedy Jam. In 2012 he appeared on BET's Comic View and also appeared at the Just for Laughs comedy festival in Montreal. In 2013 he was named Comedy Central's "#1 Comic to Watch".

In 2015 he appeared on the Comedy Central web and television series This is Not Happening and told his story of a prison riot where he learned the meaning of the phrase "Mexican got on boots!"[2] The video of this story received 12 million hits on YouTube. Siddiq also appeared on AXS TV's Gotham Comedy Live (filmed at the Gotham Comedy Club) that same year. In 2016 he released his first half hour special on Comedy Central.

In 2017 he began production on his one-hour special Ali Siddiq: It’s Bigger Than These Bars, which was filmed at the Bell County Jail in Belton, Texas. Released on Comedy Central in 2018, Siddiq can be seen performing in front of a group of inmates interspersed with scenes of him sitting down with smaller groups of incarcerated men and women in their cells, as well as with prison administrators.

In 2019 Siddiq appeared on D.L. Hughley's late night talk show The D.L. Hughley Show, as well as the Comedy Central series This Week at the Comedy Cellar, in addition to being a finalist on the NBC comedy competition series Bring the Funny.

Siddiq has released five comedy albums: Talking Loud Saying Something (Live at the Improv) released in 2010; Enjoy Your Life and Freedom of Speech, which were both released in 2013; Damaged Goods released in 2016 and The Prison Manual released in 2019

In January 2021, Siddiq joined the Funky Larry Jones afternoon drive show on KMJQ (102.1 FM) in Houston