Geographic mobility and favourable educational policies have resulted in a rapid expansion in international education in recent decades. International education not only provides significant economic benefits and intellectual progression at the national level but also equips individuals with a good understanding of the educational, linguistic, social and cultural diversities that characterize our world. For international students, being successful academically and socially requires more than just a high level of English language proficiency. Personal factors such as motivation, self-efficacy, personal values and self-regulation are also significant factors in student success. This article addresses the importance of such personal factors, using a structural equation modelling approach that allows us to examine the complex relationship between personal factors, students' English language proficiency and academic achievement. The participants were 341 English as a second language (ESL) international students who were attending the final semester of their Foundation Studies programme which prepared them for undergraduate entry at an Australian university. It was found that motivation, self-regulation, self-efficacy and English language proficiency were significant learner factors explaining not only English language learning but also academic achievement. The study suggests the need for language classroom teaching and university support that incorporates such personal factors with academic language content as a way to maximize students' learning outcomes.