This dissertation combines the development of infrared instrumentation with the application of infrared imaging and spectroscopy to studies of the highest and lowest mass products of the star formation process. I supported the development and commissioning of FLITECAM, a ~1-5 μm imager and spectrograph for SOFIA (Stratospheric Observatory for Infrared Astronomy), as the UCLA FLITECAM Instrument Scientist, and used FLITECAM to probe high-mass star formation. In parallel, I used the NIRSPEC spectrograph at the W.M. Keck Observatory to study the lowest mass products of star formation, brown dwarfs. Here, I present my FLITECAM development work and an overview of FLITECAM's in-flight performance in both imaging and spectroscopy modes. I also discuss early science with FLITECAM, including an imaging survey of the NGC 2024 and W3 star-forming regions using FLITECAM's Paschen-α (1.87 μm) and Polycyclic Aromatic Hydrocarbon (PAH; 3.3 μm) filters. Additionally, I present the results of a Keck/NIRSPEC spectroscopic follow-up survey of 13 late-type T dwarfs (T6-T9) with unusually red or blue J-H colors. Previous work suggests that J-H color outliers may represent the high-gravity, low-metallicity (old) and low-gravity, high-metallicity (young) extremes of the late-T dwarf population. I find that the T dwarf color outliers in this sample are more homogenous than expected, though three objects stand out as potentially old and a fourth object stands out as potentially young. To characterize the physical properties of the sample, I compare the target spectra to both spectral standards and publicly available atmospheric model grids.