Smith had started an open mic night at the Get Me High lounge in November 1984 called the Monday Night Poetry Reading. Even as poets scoffed at artists "performing" their work, rather than genteely "reading" it, the event grew in popularity. Smith saw his approach as an "up yours" to establishment poets he considered snooty and effete, because at their events, "no one was listening".

According to Smith, who once attended a conventional reading with his manuscripts concealed inside a newspaper,

With a like-minded troupe, Smith hosted the first poetry slam at the Get Me High Lounge in the Bucktown neighborhood in 1986. The event soon migrated to the Green Mill, a tavern and jazz lounge in Chicago's Uptown neighborhood, where it has remained ever since. Other poets in the first slam were Mike Barrett, Rob Van Tuyle, Jean Howard, Anna Brown, Karen Nystrom, Dave Cooper, and John Sheehan, all fellow members of the Chicago Ensemble of Poetry. According to Smith, the first slam was more variety show than competition. Though all slams vary in format, Smith is considered responsible for key features, including the selection of judges from the audience and cash prizes.

As stated in the PBS television series, The United States of Poetry, a “strand of new poetry began at Chicago's Green Mill Tavern in 1987 when Marc Smith found a home for the Poetry Slam.” Smith had found a crowd-inclusive, entertaining method for nurturing the poetry scene. Since then, the poetry slam has spread throughout the world, exported to over 500 cities large and small.

In the book, Words in Your Face: A Guided Tour Through Twenty Years of the New York City Poetry Slam, author Cristin O'Keefe Aptowicz describes the influential Smith:

Since July 1986, Marc has run the Uptown Poetry Slam, a three hour show featuring an open mic (1 hour), feature--poet or professional touring act (1 hour), and the poetry slam. It is the longest running, weekly poetry show in the country, and one of the longest running shows in Chicago history.

In 1990, the first National Poetry Slam was held in San Francisco (with three city teams attending including Chicago and New York City), and has continued to rotate among cities. The National Poetry Slam currently sees over 80 teams of poets vying for the title. In 2008 and 2009, the National Poetry Slam will be held in Madison, WI. NPS 2008 - Home

Over the years, Smith has turned down offers to commercialize the slam, including movie offers and bids for corporate sponsorship. Smith says that what he considers to be Slam's increased commercial exploitation, and Def Poetry Jam in particular, as having "diminished the value and aesthetic of performance poetry." This, combined with a continuing lack of Slam's recognition by "big literature festivals and institutions" in America, has led Smith to become more invested in performance poetry in Europe, where he says the "audiences are growing over there. And the aesthetic is growing and evolving.”

Smith has published several books about the poetry slam movement, as well as publishing two books of his own work. He tours extensively, performing his own, blue-collar, Carl Sandberg influenced poetry and hosting poetry slams. He also tours with a show titled, Sandburg to Smith-Smith to Sandburg, which combines the work of both poets with live jazz.