Dead Island has surpassed five million sales globally, according to publisher Deep Silver.
The firm said the milestone figure includes retail and digital sell through and claimed the title still "maintains an exceptional strong sales rate in all channels".
Klemens Kundratitz, CEO of Deep Silver parent company Koch Media, said of the achievement: "While others focus on ever-increasing development budgets and driving brand messages via ballooning marketing expenditures, Deep Silver stands for hitting the zeitgeist, innovation and fresh gameplay.
"Dead Island has an incredibly active and enthusiastic community, and we are thrilled to welcome the five millionth player to the world of Banoi. This once again proves that venturing into new waters in terms of games publishing does matter for success and that even at the end of a console cycle new IPs can be created and nurtured into lasting franchises."
Koch Media commercial director Menno van der Bil also said the game's success "has proven that we're on the right track with our overall IP strategy for Deep Silver. Further new IPs with an innovative angle and maybe even surprising touch can be expected from Deep Silver".
Additionally, he views the title's performance as "a particularly good omen for the projected sales of Dead Island: Riptide", the upcoming series follow-up.
Deep Silver has confirmed a Dead Island: Riptide release date of April 23 in North America and April 26 internationally.
The critically divisive Dead Island launched in September 2011. We said in our 6.5/10 Dead Island review: "This budget zombie thriller ain't too pretty but could manage to capture a cult following."
Included in the deal is the purchase of Champaign, Illinois-based Volition
Germany headquartered Koch Media confirmed last month that it had purchased the Saints Row IP, along with developer Volition and the Metro IP for a total of $28 million, calling the acquisition a "perfect fit" for Deep Silver.