Trivia

Is a skilled musician and wrote the songs contributed by his character, Charlie Kelly, in Siempre hay sol en Filadelfia (2005).

Charlie and his wife Mary Elizabeth Ellis met as fellow theater actors in New York City in 2001.

He was roommates for a time with actor Jimmi Simpson who would later play the part of Liam McPoyle on Day's show Siempre hay sol en Filadelfia (2005).

In 2004, he and his future wife, Mary Elizabeth Ellis, played incestuous siblings on the Reno 911! (2003) episode, Not Without My Mustache (#2.7).

He was the only person in his nuclear family not to have doctorate degree until 2014, when his Alma Mater, Merrimack College, awarded him an honorary doctorate.

His family's original surname was "Del Giorno". His father is of Italian and Irish ancestry, and his mother has English, with remote Irish and Welsh, roots. Many of his mother's family lines have been in the United States, specifically in New England, since the 1600s.

Charlie and his wife, Mary Elizabeth Ellis, had their first child, a son named Russell Wallace Day, on December 15, 2011.

He hosted the November 5, 2011 episode of Saturday Night Live (1975). He is the second cast member from Siempre hay sol en Filadelfia (2005) to host SNL, after Danny DeVito.

Best friends and co-producers in everything with Terry McGinnis, including universal matters of creation, destruction and everything, especially marital and relationship problems.