In the last two decades, Internet gambling (IG) has emerged as a medium in which to gamble. This research aimed to increase understanding of IG by examining routes in and out of problem IG, and also investigating similarities and differences between men and women, players of different IG activities (betting, poker, casino, lottery), and problem and non-problem gamblers (PGs, NPGs). A mixed-method approach was used. Initially, 62 UK Internet gamblers (31 male, 31 female; 32 NPG, 30 PG) participated in semi-structured interviews analysed using the Grounded Theory Method (Strauss & Corbin, 1998). Key findings were translated into hypotheses which were tested in a bespoke online survey, completed by 266 UK Internet gamblers (204 male, 62 female; 182 NPG, 58 PG). Qualitative findings indicated multiple influences for initiating IG, and factor analysis of the quantitative data indicated six initiating factors; utility of IG, value for money, social introduction, alternative social environment, competitiveness and needing something to do. Men were more influenced than women by value for money and utility of IG. Bettors were more influenced by utility than players from other gambling domains, casino players by the attraction of an alternative social environment online, and poker players, by competitiveness and needing something to do. PGs were more influenced than NPGs by an alternative social environment, competitiveness and needing something to do. A ‘vulnerability-compensation effect’ was noted, where vulnerabilities in daily life could be compensated for by engagement with Internet gambling. Continuing, increasing and decreasing IG involvement was influenced by seven categories of events and motivations; financial interests and concerns, enjoyable leisure activity, skill development, life events, emotions and escape, social influence, utility of IG features and time. Convenience had the biggest impact on increasing IG involvement across all gamblers. Men were more influenced than women to increase IG by skill development, women were more influenced by life events, emotions and escape. Poker players were influenced more than players in other domains by skill development. PGs were more influenced than NPGs to increase due to finances, and life events, emotions and escape. Motivations for starting, continuing, escalating and reducing gambling involvement included two new behavioural drivers for IG not specifically captured in existing gambling motivation research; the utility of IG features, and time, as in the opportunities and constraints on available time. Motivations were different across key gambler variables, and their effects changed over a gambler’s journey. Participants indicated that life events, emotions and escape had a strong impact on gambling behaviour, and also suggested safe play and resilience to harm could be developed as protective factors. Both of these issues, along with the impact on time as a possible problem IG marker, have potential to influence social responsibility strategies. From qualitative and quantitative findings, an integrated IG model was created, which suggests problem IG results from a series of escalations influenced by the seven categories of continuation events. The model potentially offers a vehicle for systematic testing and comparison of factors influencing stability and change of IG involvement.