Indoleacetic acid (IAA) can act as a phytohormone to modulate plant growth and development, thus persistent search for IAA-producing microbes is underway for a potential application in promoting plant growth. In this paper, an IAA-producing bacterium was obtained from maize rhizosphere in biochar-amending field. This strain is a Gram-negative and facultative anaerobic rod. Phenotypic examination and 16S rRNA gene sequencing suggest that this strain is a new strain of the Enterobacter species. We designated this strain LX3. LX3 produced up to 200 mg/L of IAA in nutrient broth and promoted barley development and increased plant chlorophyll level. This suggests that LX3 has potential as a biofertilizer.