Inconel 718 is the most widely used Ni-superalloy for aero-engine parts capable of withstanding high temperature. Laser-directed energy deposition process is gaining massive popularity in these industries due to its ability to produce near-net shape parts in less time compared to other laser-based additive manufacturing techniques. However, the primary concern for this type of process is lower material utilization efficiency or powder catchment efficiency (PCE). Therefore, this article aims to evaluate the effects of input processing conditions, i.e., laser power (LP) and scan speed (SS), on powder catchment efficiency (PCE), dilution (D), and aspect ratio (AR) simultaneously for deposition of Inconel 718 to improve the powder utilization keeping all the other two parameters within the permissible limits. From the results, it can be inferred that PCE is improving with the increase of LP and the maximum PCE reached is 48.04% at LP of 1000 W and SS of 400 mm/min. The thermal signature of the molten pool during deposition is recorded with an infrared pyrometer to calculate the solidification cooling rate (CR) during deposition. The effects of CR on the resultant grain size are studied; with the increasing scan speed, the CR is increasing significantly, which is the primary reason for grain refinement. Microhardness of the deposited tracks increases with the increment in CR and reduction in grain size; minimum grain size and maximum hardness of 3.03 μm and 270.3 ± 8.1 HV0.2, respectively, were achieved in this study.