Selectins mediate leukocyte rolling, trigger β₂-integrin activation, and promote leukocyte recruitment into inflamed tissue. E-selectin binding to P-selectin glycoprotein ligand 1 (PSGL-1) leads to activation of an immunoreceptor tyrosine-based activation motif (ITAM)–dependent pathway, which in turn activates the spleen tyrosine kinase (Syk). However, the signaling pathway linking Syk to integrin activation after E-selectin engagement is unknown. To identify the pathway, we used different gene-deficient mice in autoperfused flow chamber, intravital microscopy, peritonitis, and biochemical studies. We report here that the signaling pathway downstream of Syk divides into a phospholipase C (PLC) γ2– and phosphoinositide 3-kinase (PI3K) γ–dependent pathway. The Tec family kinase Bruton tyrosine kinase (Btk) is required for activating both pathways, generating inositol-3,4,5-trisphosphate (IP₃), and inducing E-selectin–mediated slow rolling. Inhibition of this signal-transduction pathway diminished Gα_i-independent leukocyte adhesion to and transmigration through endothelial cells in inflamed postcapillary venules of the cremaster. Gα_i-independent neutrophil recruitment into the inflamed peritoneal cavity was reduced in Btk^−/− and Plcg2^−/− mice. Our data demonstrate the functional importance of this newly identified signaling pathway mediated by E-selectin engagement.