This chapter explores Tim’s LAL development, his assessment identity construction and the difficulties he went through and the opportunities he embraced over three semesters. Unlike Rachel, Tim, as a novice English instructor, began with substantial assessment knowledge obtained from his comprehensive assessment education. However, he did not advance this knowledge over the semesters as he was not motivated to do so due to the influence of his family, institution and students. Despite his assessment knowledge, Tim’s assessment activities were test-orientated, which led to his uncertainty about his identity as an assessor. He integrated self-and peer assessment into writing classes without seeking to improve their effectiveness. While he preferred giving individualised feedback, he felt powerless when feedback was not effectively utilised. Tim was concerned about assessment criteria and enthusiastically discussed with peers when taking a training programme. However, he did not take this opportunity to enhance his LAL in this area. In addition, his participation in a teaching contest did not significantly boost his LAL. Over time, through reflecting on his responsibilities, Tim gradually acknowledged his identity as an assessor, but preferably considering himself to be a life mentor and acting as a lenient marker.