Wong-Ng was a research associate and lecturer in the chemistry department at University of Toronto. From 1981 to 1985, she was a critical review scientist at the International Centre for Diffraction Data. Wong-Ng was a research scientist in the chemistry department at University of Maryland, College Park and a research associate in the ceramics division at the National Bureau of Standards from 1985 to 1988. Since 1988, Wong-Ng works as a research chemist in the ceramics division at the National Institute of Standards and Technology. She served as president the Association of NIST Asian Pacific Americans from 2000 to 2003.
Wong-Ng's research interest includes materials for energy applications, thermoelectric standards, metrology, and data, sorbent materials for sustainability, and high throughput combinatorial approach for novel materials discovery and property optimization for energy conversion applications. She also researches crystallography, phase equilibria, and crystal chemistry of energy materials to understand their structure and property relationships. Structural studies involve synchrotron X-ray and neutron diffraction techniques.