David J. Bradley joined IBM as a senior associate engineer immediately after receiving his Ph.D. from Purdue in 1975. He worked on the advanced technology for the Series/1 system and in 1978 moved to entry level systems where he was responsible for developing the I/O system for the System/23 Datamaster. In September 1980 Bradley became one of the "original 12" engineers working on the IBM Personal Computer and was responsible for the ROM BIOS code. That led to his promotion to senior engineer in September 1981 and in November to an appointment to manage the BIOS and diagnostics for the IBM PC XT. In February 1983 Bradley formed the Personal Systems Architecture Department and in 1984 became the second-line manager for the Personal System 2 Model 30.

In 1986 Bradley was named a senior technical staff member and later that year began an assignment on the Corporate Development Staff. In November 1987 he returned to Boca Raton as manager of advanced processor design. His group was responsible for advanced processor complex development including the 486/25 Power Platform and the PS/2 Models 90 and 95. Early in 1991 he became manager of systems architecture for the Entry Systems Technology group and in December 1992 became the architecture manager for the new group building a personal computer using the PowerPC RISC microprocessor. He returned to the PC Company as manager of architecture in October 1993 and continued in that position after his move to North Carolina in 1995. Bradley holds seven U.S. patents and has served as adjunct professor of electrical and computer engineering at Florida Atlantic and at North Carolina State universities.