All people who met Mezzofanti describe him as a humble, frugal and congenial man.

He had a frugal lifestyle, waking up early in the morning and studying languages until late at night.

He never married. He remained very close to his only sister, 10 years older than him. He had frequent contacts with his numerous nephews.

He was always found in the company of young men (most of which studied for priesthood).

He was very loyal to his friend Pople Gregory XVI.

He was not a great writer but wrote some scholarly articles.