The crystallization behavior of a newly developed polyvinyl alcohol with 1,2-diol side-chains (DPVA) was investigated for different 1,2-diol side-chain, magnesium acetate, and sodium acetate contents. Crystallization by stepwise cooling, isothermal and non-isothermal crystallization (the actual cooling process in melt molding) experiments were conducted. Upon crystallization analysis by stepwise cooling, the end surface energy of DPVA increased as the 1,2-diol side-chain content was increased. The isothermal crystallization process exhibited longer half crystallization times at high 1,2-diol side-chain and magnesium acetate contents. Upon Kissinger analysis of the non-isothermal crystallization results, the effect of the acetate salts was found to be smaller than that for isothermal crystallization, while the smaller number of repeating units in the lamellar structure, reflecting a higher side-chain 1,2-diol content, resulted in a smaller activation energy for DPVA crystallization. In addition, analyses by the Ozawa method and the Kissinger Plot suggested possible changes in the mode and dimension of the crystal growth of DPVA.