Dopamine receptors, including D1- and D2-like receptors, are important therapeutic targets in a variety of neurological syndromes, as well as cardiovascular and kidney diseases. Here, we present five cryoelectron microscopy (cryo-EM) structures of the dopamine D1 receptor (DRD1) coupled to Gs heterotrimer in complex with three catechol-based agonists, a non-catechol agonist, and a positive allosteric modulator for endogenous dopamine. These structures revealed that a polar interaction network is essential for catecholamine-like agonist recognition, whereas specific motifs in the extended binding pocket were responsible for discriminating D1- from D2-like receptors. Moreover, allosteric binding at a distinct inner surface pocket improved the activity of DRD1 by stabilizing endogenous dopamine interaction at the orthosteric site. DRD1-Gs interface revealed key features that serve as determinants for G protein coupling. Together, our study provides a structural understanding of the ligand recognition, allosteric regulation, and G protein coupling mechanisms of DRD1. Display omitted •Structures of DRD1-Gs in complex with catechol-based and non-catechol agonists•Key polar interaction network is involved in DRD1 activation•Specific features for agonists interaction and Gs coupling of DRD1 are determined•Structure of DRD1-Gs complexed with dopamine and positive allosteric modulator•Structural basis of allosteric regulation of DRD1 by LY3154207 is investigated The cryo-EM structures of DRD1 coupled to its G protein, in complex with important agonists, elucidates the mechanism of G-protein-coupled selectivity and will facilitate future drug discovery and design.