Short vegetative phase (SVP) like genes play a key role in floral transition and floral meristem identity. Although SVP-like genes have been isolated from various plant species, their orthologs have not been characterized in the important day-neutral ornamental plant Chrysanthemum morifolium Ramat. Here, a MADS-box gene was cloned from C. morifolium ‘Jinbudiao’ and designated as CmSVP. The open reading frame of CmSVP comprises 672 bp encoding a putative protein of 223 amino acids. Bioinformatics analyses showed that the gene was a member of the SVP gene family with homology to MADS-box transcription factors. Real-time polymerase chain reaction results showed that CmSVP is preferentially expressed in the shoot apex and leaves and its expression is decreased in both flower buds and flowers. Transcription of CmSVP in Arabidopsis plants showed overexpression of CmSVP delayed blossoming for up to 30 d. It also inhibited development of apical flower in the main stem, which resulted in an abortive bud or inflorescence. Additionally, the transgenic Arabidopsis plants contained increased basal inflorescences and branches, whorled leaves, opposite leaves in branches, and absence of main stem cauline leaves. These findings suggest that CmSVP is not only involved in flower timing and floral meristem identity, but also regulates inflorescence architecture.