A trapped vortex fuel injector includes a main body having an annular portion and a semi-annular portion coaxially aligned with the annular portion. The semi-annular portion extends downstream from the annular portion. An inner wall and an opposing outer wall of the main body extend between the annular and semi-annular portions. The annular portion at least partially defines a combustion air flow passage through the trapped vortex fuel injector. The semi-annular portion defines a trapped vortex pre-mix zone downstream from the combustion air flow passage. The main body further defines a fuel circuit that is fully circumscribed within the main body and that extends between the annular portion and the semi-annular portion. A plurality of fuel injection ports provide for fluid communication between the fuel circuit and the trapped vortex pre-mix zone. The main body may be fabricated using an additive manufacturing process.