As a non-profit project, the Lemp is known for operating by a DIY ethic of show promotion and venue maintenance, relying on a team of volunteers to help with day-to-day functions. Inspired by the straight edge movement and Fugazi's business ethics, the shows at Lemp are always all-ages, drug and alcohol free, and cost five dollars for admission at the door, with the majority of the money paid to the music performers directly. The venue also strictly avoids booking bands and musicians with a commercialized sound and/or music industry standard of practice, or any performer who promote "violent or reckless behavior" or "a discriminatory, lewd, degrading or immoral message." The Lemp has long been known for hosting experimental music acts, especially ones classifiable as noise rock, art rock, or noise music. Other genres it has known to frequently select includes but are not limited to: free improvisation, electro-acoustic, folk, hardcore, punk, post-punk, math rock, indie rock, emo revival, post-hardcore, grindcore, and no wave. Additionally, the Lemp hosts poetry and theater. In addition to its regular concerts, Lemp is also acclaimed for hosting a three-day festival called NoisefeSTL, which is known for showcasing experimental performers from the Midwest "whose work could be associated with noise." NoisefeSTL inaugurated in October 2004, and has occurred annually until its latest showcase in 2013.
Since 2009, Lemp has operated a program called Orchestrating Diversity, "a social change program" that provides free education in orchestral music to inner-city youth of Saint Louis. Students participate in an eight-week summer intensive that provides music instruction for eight hours per day, as well as an after-school program throughout the regular school year. They are taught music theory, history and musicianship at a college level. They are also taught to perform symphonic music in a large ensemble known as the Orchestrating Diversity Urban Youth Orchestra, and are given free private instruction on their instruments by professional musicians, college faculty members, and student volunteers from Washington University in Saint Louis and Saint Louis University. In the summer of 2012, Orchestrating Diversity began the Junior Urban Music Program, which provides extensive beginners music classes to children aged 5–8 years old. Because of JUMP's success in its inaugural year, it was expanded in the summer of 2013 to provide classes in East Saint Louis, Illinois. Orchestrating Diversity is a nucleo of El Sistema USA, which is a network of similar programs in the United States modeled off of El Sistema in Venezuela.
