Recombinant NK cells, and especially recombinant NK-92 cells express a chimeric antigen receptor (CAR) having an intracellular domain of FcεRIγ. Notably, CAR constructs with an intracellular domain of FcεRIγ had a substantially prolonged duration of expression and significantly extended cytotoxicity over time. The CAR may be expressed from RNA and DNA, preferably as a tricistronic construct that further encodes CD16 and a cytokine to confer autocrine growth support. Advantageously, such constructs also enable high levels of transfection and expression of the recombinant proteins and provide a convenient selection marker to facilitate rapid production of recombinant NK/NK-92 cells.