This article describes a study which investigated how explicit strategy instruction may shape student use of metacognitive knowledge and in what ways this knowledge promotes self-regulation in the learning of writing. From a class of a 2-year associate degree programme in Hong Kong, which experienced a 15-week process-oriented writing course emphasizing instruction in diverse composing strategies ranging from planning to revision, four participants were chosen. They provided data consisting of stimulated recalls, individual interviews, language learning histories, and text analysis. The findings indicate that explicit strategy instruction in writing was likely to make students more self-regulated, strategic, and resourceful in coping with diverse writing tasks, although not all four writers enjoyed the same level of success throughout the course. Three of them expressed a heightened awareness of audienceship and enhanced text knowledge. They also showed gradual development of metacognitive knowledge, including planning, reorganizing, and problem-solving strategies in the composing process.