Charles Wayne Day, also known as Bing Day, was a distinguished American guitarist and baritone bluesman, born on August 5, 1942, in Chicago, Illinois. His musical journey began at an early age, with his talents emerging by the age of three. At 15, he recorded his first single, "Pony Tail Partner," under the name Bing Day with Federal Records in 1957. Over the next decade, he continued to record singles, sometimes using the alias Ford Hopkins.

In 1965, Day moved to Los Angeles, California, where he became a pivotal yet often unrecognized figure in rock and roll. He joined Johnny Rivers' Band as a bassist and crafted the iconic lead guitar riff for Rivers' "Secret Agent Man." His collaboration with The Mamas & the Papas in 1967 saw him playing bass and second guitar on hits like "Monday, Monday" and "California Dreamin'."

Throughout the 1970s and 1980s, Day contributed to numerous recordings, including Shel Silverstein's "Freaker's Ball," and composed for soundtracks such as "Fritz the Cat." He also performed alongside musicians like Luther Tucker and Merl Saunders. In 1986, he formed his own band and continued to perform locally in California.

Day resided in Fairfax, California, from 1969 until his death on March 10, 2008, in Healdsburg, California. After his passing, it was revealed that he was the biological father of Owen Vanessa Elliot, daughter of Cass Elliot from The Mamas & the Papas. A memorial service and parade were held in his honor in Fairfax on March 22, 2008. His legacy remains influential in the blues and rock music genres.