An active chamber musician and improviser, Dennis Sullivan has shared the stage with leading contemporary music ensembles and improvisers such as The Argento New Music Project, Either/Or, The International Contemporary Ensemble, Wavefield, Pink Noise, ECCE Ensemble, Ensemble Court Circuit (Paris), Brandon Lopez, Erin Rogers, Dana Jessen, Ensemble Pamplemousse, Wavefield Ensemble, Newband, The Darmstadt Preistrager Forum, and Ensemble Modern Academy.