Dennis Day (May 21, 1916, New York City – June 22, 1988, Los Angeles, California), born Owen Patrick Eugene McNulty, was an Irish-American singer and radio and television personality.

Day was born and raised in New York City, the son of Irish immigrants. His father was a stationary engineer. Day graduated from Cathedral Preparatory Seminary in New York City, and attended Manhattan College in the Bronx, where he sang in the glee club.

Radio
Day appeared for the first time on Jack Benny's radio show on October 8, 1939, taking the place of another famed tenor, Kenny Baker. He remained associated with Benny's radio and television programs until Benny's death in 1974. He was introduced (with actress Verna Felton playing his mother) as a young (nineteen year old), naive boy singer — a character he kept through his whole career. His first song was "Goodnight My Beautiful".

Besides singing, Dennis Day was an excellent mimic. He did many imitations on the Benny program of various noted celebrities of the era, such as Ronald Colman, Jimmy Durante, and James Stewart.

 
From 1944 through 1946, he served in the US Navy as a Lieutenant. On his return to civilian life, he continued to work with Benny while also starring his own show, A Day in the Life of Dennis Day (1946-1952). Day's having two programs in comparison to Benny's one was the subject of numerous jokes and gags on Benny's show, usually revolving around Day rubbing Benny's, and sometimes other cast members and guest stars' noses in that fact.

Television
His TV series, The Dennis Day Show (aka The RCA Victor Show) was telecast from 1952 to 1954. Between 1952 and 1978, he made numerous TV appearances as a singer and actor (such as ABC's The Bing Crosby Show) and voice for animation (such as the Walt Disney feature Melody Time, handling multiple characters).

In 1948, Day married Peggy Almquist; the marriage lasted until his death in 1988. The couple had ten children. One of his brothers was wed to actress/singer Ann Blyth.

Dennis Day died of Lou Gehrig's disease at age 72 in Los Angeles, California. His star on the Hollywood Walk of Fame is at 6646 Hollywood Boulevard. He is interred in Culver City's Holy Cross Cemetery.