Kinetic inductance detectors (KIDs) are a type of athermal pair-breaking superconductingdetectors. Several superconductors have an energy gap on the order of 0.1eV, which makes KIDs well-suited for mm and sub-mm wave observations. Compared to their counterparts in this regime, KIDs have innate multiplexing capabilities which makes them ideal in experiments requiring a large number of detectors. The first half of this thesis discusses the design, fabrication, and characterization of a prototype KID array for CMB observations, made out of Al/Nb KIDs coupled to a Nb/SiN/Nb microstrip. Another target of the future observations using KIDs will be surveying dusty star-forming galaxies (DSFG). They are believed to make up the light emitted in the universe in the infrared and mm-wave regime, known as the cosmic infrared background (CIB). However, the link between DSFGs and the sources that make up the cosmic optical background is still unclear. The second half of this thesis describes the characterization of mm-wave emission in the SPT-SZ, SPTpol, and Herschel SPIRE bands of optically-selected galaxies from the DES Year 3 catalog.