<p>Anaplastic lymphoma kinase (Alk) signaling is important in a variety of biological contexts such as cell type specification, regulation of metabolic and endocrine programs, behavior, and cancer. In this work, we generated a Tango GPCR assay-based, dimerization-sensitive Alk activity reporter (Alk^Tango) and followed receptor activation throughout <i>Drosophila</i> development. Alk^Tango reports Alk activation in embryonic and larval tissues previously linked to Alk signaling. Remarkably, Alk^Tango was active in the heart of <i>Drosophila</i> larvae and adult flies. We show that cardiomyocytes express Alk from late embryonic stages to adulthood, while <i>jeb</i> expression in pericardial cells coincided with Alk^Tango activity. Perturbation of cardiac Alk signaling leads to decreased adult survival as well as lower fitness and increased lethality in response to heat stress. In keeping with a role for Alk, heart measurements reveal arrythmia and irregular muscle contraction upon ligand stimulation. Finally, activation of cardiac Alk signaling induces hyperplasia in the accessory wing hearts of adult flies.</p>