When wargame giant Avalon Hill and then-current computer game publishers were not interested in his first title, Joel Billings had to found his own company to publish and distribute his computer wargames. SSI was the dominant force in computer wargames from then (1981) into the early 1990s, holding its own against Avalon Hill's own efforts and other competitors.

In the mid 1980s, two of SSI's more prolific developers left to form their own company, SSG. The split appears to have been at least as much a result of the two living in Australia as of any business or creative reasons.

In the late 1980s, SSI signed a deal with TSR, Inc., to publish official Dungeons and Dragons computer games. The "Gold Box" D&D games took the company in new directions. Although SSI never stopped publishing war games, the D&D license quickly became the main source of income and produced their best-known products.

The loss of the D&D license to Interplay was the swan song for SSI as an independent company. No longer dominant in their original wargame market and suddenly without their primary franchise, the company was acquired by Mindscape in 1994. It changed hands several times after that - from Mindscape to The Learning Company, Mattel Interactive, The Gores Group and finally to Ubi Soft. Ubi Soft used the SSI logo and name on some of their titles, including Pool of Radiance: Ruins of Myth Drannor and Destroyer Command, but has since retired the brand.