Many growth regulatory stimuli promote cAMP response element-binding protein (CREB) Ser133 phosphorylation, but the physiologically relevant CREB-Ser133 kinase(s) in the heart remains uncertain. This study identifies a novel role for protein kinase D (PKD) as an in vivo cardiac CREB-Ser133 kinase. We show that thrombin activates a PKCδ-PKD pathway leading to CREB-Ser133 phosphorylation in cardiomyocytes and cardiac fibroblasts. α1-Adrenergic receptors also activate a PKCδ-PKD-CREB-Ser133 phosphorylation pathway in cardiomyocytes. Of note, while the epidermal growth factor (EGF) promotes CREB-Ser 133 phosphorylation via an ERK-RSK pathway in cardiac fibroblasts, the thrombin-dependent EGFR transactivation pathway leading to ERK-RSK activation does not lead to CREB-Ser133 phosphorylation in this cell type. Adenoviral-mediated overexpression of PKCδ (but not PKCε or PKCα) activates PKD; PKCδ and PKD1-S744E/S748E overexpression both promote CREB-Ser133 phosphorylation. Pasteuralla multocida toxin (PMT), a direct Gαq agonist that induces robust cardiomyocyte hypertrophy, also activates the PKD-CREB-Ser133 phosphorylation pathway, leading to the accumulation of active PKD and Ser133- phosphorylated CREB in the nucleus, activation of a CRE-responsive promoter, and increased Bcl-2 (CREB target gene) expression in cardiomyocyte cultures. Cardiac-specific Gαq overexpression also leads to an increase in PKD-Ser744/ Ser748 and CREB-Ser133 phosphorylation as well as increased Bcl-2 protein expression in the hearts of transgenic mice. Collectively, these studies identify a novel Gαq-PKCδ-PKD-CREB-Ser133 phosphorylation pathway that is predicted to contribute to cardiac remodeling and could be targeted for therapeutic advantage in the setting of heart failure phenotypes.