This study investigates the influence of the semantic heaviness of verbs (i.e., heavy or light verbs) and language proficiency on second language (L2) learners' use of constructional information in a sentence-sorting task and a corpus analysis. Previous studies employing a sentence-sorting task demonstrated that advanced L2 learners sorted English sentences according to argument structure constructions rather than lexical verbs. However, these studies collapsed both heavy (e.g., "cut," "throw") and light (e.g., "get," "take") verbs into a single variable, blurring the effects of the semantic heaviness of the verbs. The present study designed a sentence-sorting task involving heavy and light verbs as separate variables and administered it with advanced and intermediate adult learners of English (Experiment 1). Results showed that while advanced learners showed construction-dominant sortings regardless of the heaviness of a verb, intermediate learners produced construction-based sortings only in the light verb condition. A corpus analysis of learner essays (Experiment 2) revealed that intermediate learners relied on light verbs in producing constructions more strongly than advanced learners and native speakers. These findings suggest that L2 proficiency modulates the degree to which the semantic heaviness of a verb affects learners' use of constructional knowledge in sorting and producing English sentences.