The conventional (non‐genetically modified) soybean [Glycine max (L.) Merrill] line TN15‐4009 (Reg. no. GP‐437, PI 691608) was released by University of Tennessee Agricultural Research in 2019 as a germplasm line on the basis of its high seed yield potential in the southern region of the United States and resistance to soybean cyst nematode (SCN), southern root knot nematode, and peanut root knot nematode. The objective of its development was to create a high‐yielding SCN‐resistant soybean line. Progeny rows were selected based on adapted maturity, lodging resistance, disease resistance, and pod density and were entered in yield tests from 2015 through 2018. TN15‐4009 has white flowers and tawny pubescence. The pods have a tan pod wall, and the seed is yellow with a smooth seed coat. The seed size is approximately 13.6 g 100 seed−1, which was significantly greater than that of ‘Ellis’ in the 2018 USDA Uniform Test. In that test, TN15‐4009 matured 1 d earlier than Ellis and the same as ‘AG 4835’, indicating that the relative maturity of TN15‐4009 is approximately 4.8. Soybean line TN15‐4009 is resistant to SCN HG type 5.7 (score = 1) and HG type 2.5.7 (score = 1), resistant to southern root knot nematode (score = 1), and resistant to peanut root knot nematode (score = 1.3). TN15‐4009 is susceptible to stem canker.