Effective cancer care depends on inter-sectoral and inter-professional communication. General Practitioners (GPs) play a pivotal role in managing the health of most Australians, but their role in cancer care is unclear. This qualitative study explored GPs’ views of this role and factors influencing their engagement with cancer care. Twelve metropolitan and non-metropolitan GPs in Queensland, Australia, were recruited between April and May 2008, and three focus groups and one interview were conducted using open-ended questions. The transcripts were analysed thematically. The first theme, GPs’ perceptions of their role, comprised subthemes corresponding to four phases of the trajectory. The second theme, Enhancing GPs’ involvement in ongoing cancer care, comprised subthemes regarding enhanced communication and clarification of roles and expectations. GPs’ role in cancer care fluctuates between active advocacy during diagnosis and palliation, and ambivalent redundancy in between. The role is influenced by socioeconomic, clinical and geographical factors, patients’ expectations and GPs’ motivation. Not all participants wanted an enhanced role in cancer care, but all valued better specialist–GP communication. Role clarification is needed, together with greater mutual trust between GPs and specialists. Key needs included accessible competency training and mentoring for doctors unfamiliar with the system. Existing system barriers and workforce pressures in general practice must be addressed to improve the sharing of cancer care. Only one metropolitan focus group was conducted, so saturation of themes may not have been reached. The challenges of providing cancer care in busy metropolitan practices are multiplied in non-metropolitan settings with less accessible resources and where distance affects specialist communication. Non-metropolitan GPs learn from experience how to overcome referral and communication challenges. While the GPs identified solutions to their concerns, the role can be daunting. GPs are motivated to provide long-term care for their patients, but need to be acknowledged and supported by the health system.