Prof. Kim's doctoral dissertation in 1990 was on the integrated microphone with LSI CMOS on a single chip. In Fall 1999, he joined the University of Southern California, Los Angeles, where he is currently a Professor of the Ming Hsieh Department of Electrical Engineering-Electrophysics. From July 1, 2009 to June 30, 2018, he chaired the Electrophysics division of the department, and oversaw a net tenure-track-faculty growth of 2.5 (from 15.25 to 17.75), 6.5 new tenure-track-faculty hires, 3 new tenure-track-faculty offers and acceptances in the last year as the chair, a net non-tenure-track-faculty growth of 4 (from 4 to 8), a net Budget-Analysts growth of 2 (from 3 to 5), and lab space growth of 4,206 sq. ft. (from 26,833 to 31,039 sq. ft.). During his tenure as the chair, US News' ranking raw score on USC EE's Graduate Program rose from 3.9 to 4.2 (out of 5.0).

From Spring 1991 to Fall 1999, he worked at the Department of Electrical Engineering in the University of Hawaii at Manoa as a faculty member. Previously, he worked at IBM Research Laboratory, San Jose, CA, NCR Corp., San Diego, CA, and Xicor Inc., Milpitas, CA as a co-op student, design engineer, and summer-student engineer, respectively.