Beginning in junior high school, he put his interest in electronics into practice by building hi-fi components and amplifiers for friends.

Oberheim enrolled at UCLA, studying computer engineering and physics while also taking music courses.

[4] In 1969, the Chicago Musical Instruments Company (CMI) approached Oberheim about his ring modulator, wanting him to become one of their manufacturing contractors.

This inspired Oberheim to design and build a phase shifter effects unit to imitate that sound.

His associations with Richard Grayson and later Paul Beaver nurtured an interest in synthesizers, and at the 1971 NAMM Show, Oberheim approached Alan R. Pearlman, founder of ARP Instruments, asked to become the company's Los Angeles dealer, and subsequently became ARP's first dealer on the west coast, selling ARP 2600 synthesizers to musicians in the Los Angeles area, including Leon Russell, Robert Lamm, and Frank Zappa.

Oberheim further expanded on the performance capabilities of 2-note polyphony in 1973, using his computer engineering experience to design the DS-2, one of the first digital-electronics-based music sequencers.

Oberheim introduced the SEM, the first synthesizer bearing his company's name, at the Audio Engineering Society convention in Los Angeles in May 1974.

[10] By 1980, Oberheim's products, by then including synthesizers, a polyphonic digital sequencer (the DSX), and a sampled-sound drum machine (the DMX) were designed to be combined to form a complete system, and could be interconnected by a proprietary Oberheim parallel bus interface that pre-dated MIDI.

[11] With the company now gathering pace, from the turn of the 1980s Oberheim now streamlined his polyphonic synthesizers into a series of major integrated keyboard instruments which proved highly popular, coming to define many records of the era, to a similar extent to Sequential's Prophet 5.

In June 1981, Roland's Ikutaro Kakehashi approached Oberheim with the idea of standardizing a communication protocol between electronic music instruments.

Tom Oberheim departed the company two years later and filed a lawsuit against his ex-lawyer for legal malpractice.

[19] In 2010, he announced plans to release the "Son of Four Voice," an updated version of his original Oberheim 4-Voice analog synthesizer.

[25] Oberheim was a core member of an informal discussion group which met weekly in a Berkeley coffeehouse.