In the title molecule, C22H21N3, the isoquinoline ring is almost planar [maximum deviation = 0.046 (1) A] and makes dihedral angles of 52.01 (4) and 14.61 (4)degrees with the pyrazole and phenyl rings, respectively. The phenyl ring and the pyrazole ring are twisted by 44.20 (6)degrees with respect to each other. The terminal C atoms of both of the ethyl groups attached to the pyrazole ring are disordered over two sites with occupancy ratios of 0.164 (7):0.836 (7) and 0.447 (16):0.553 (16). A weak intramolecular C-H...N contact may influence the molecular conformation. The crystal structure is stabilized by C-H...pi contacts involving the phenyl and pyrazole rings, and by pi-pi stacking interactions involving the pyridine and benzene rings [centroid-centroid distance = 3.5972 (10) A].