In 2001, Day began his coaching career as the wide receivers coach at Auburn Riverside High School. He then spent the next three years as the quarterbacks coach for the high school, as well as taking on the role of offensive coordinator during the final two years.[1]
In 2006, Day was hired as an offensive quality control coach at the University of Michigan, where he worked with future NFL quarterback Chad Henne.
In 2007, Day was hired by the San Francisco 49ers as an offensive quality control coach. He held the position for three years, two years under offensive coordinator Mike Martz, who later hired Day to work for him in Chicago. Day oversaw the quarterbacks in 2007, running backs in 2008, and the offensive line in 2009. He was also part of the staff that coached the South team during the 2008 Senior Bowl.
On February 5, 2010, Day was hired by the Chicago Bears as their quarterbacks coach.[2] He was recommended for the job by Chicago's offensive coordinator Mike Martz, with whom Day had worked with for two seasons in San Francisco. Day helped the Bears reach the NFC Championship game in 2010.
On January 24, 2012, Day was hired as the quarterbacks coach at the University of Connecticut, replacing Joe Moorhead, who had left for the head coach position at Fordham University.[1][4] Day called plays for the Husky offense the final 3 games of 2013 in which the offense took off, setting several school records, and leading to 3 consecutive wins against Temple, Rutgers, and Memphis.
On January 23, 2014, Day was hired by the Washington Redskins as their assistant offensive line coach.[5]
On January 12, 2016, Day was hired by the Miami Dolphins as their tight ends coach.[6]
In 2019, Day returned to the San Francisco 49ers after he was hired as their quarterbacks coach under head coach Kyle Shanahan.[7]
On January 28, 2021, Day was hired to be the Los Angeles Chargers quarterbacks coach.[8] On the heels of a Chargers loss in their AFC Wild Card game against the Jacksonville Jaguars where they blew a 27–point lead, he and offensive coordinator Joe Lombardi were both fired on January 17, 2023.[9]
On February 19, 2023, Day was hired to be the Houston Texans' senior offensive assistant.[10]
On February 8, 2024, Day was hired to return to the Los Angeles Chargers as quarterbacks coach under new head coach Jim Harbaugh.[11]
