This Quiet Night, Cook's first EP, was also released on June 28, 2011 and featured acoustic performances of select This Loud Morning album tracks.

[17] After his college graduation, he relocated to Tulsa, Oklahoma, to pursue a career in music, telling his mother, "I just want to give myself until I'm 26 years old to get a job.

[23] Axium, however, broke up in 2006 and David Cook moved to Tulsa where he joined Midwest Kings, a band he once opened for.

His white, left-handed Gibson Les Paul electric guitar has the letters "AC" on it; as Cook told TV Guide, "I have two brothers, Adam and Andrew.

"[29] Starting from the Top 12-week, he also wore (and continued to wear throughout competition) an orange wristband to support a then-7-year-old fan, Lindsey Rose, with leukemia.

[41] Cook's photo was also featured on the cover of The World Almanac and Book of Facts 2009, along with President Barack Obama and Senator John McCain.

[42] Cook worked with Espionage, Ed Roland (Collective Soul), Zac Maloy (The Nixons), Jason Wade (Lifehouse), Neal Tiemann (the Midwest Kings),[43] Kevin Griffin (Better Than Ezra), Chantal Kreviazuk, and Raine Maida (Our Lady Peace) on his self-titled, major label debut album.

[45] On Ryan Seacrest's morning show, On Air, of KIIS-FM on September 5, 2008, the singer revealed that the CD release date would be November 18, 2008.

His debut album was certified platinum by the Recording Industry Association for America (RIAA) for sales exceeding one-million units in January 2009.

[51] Other members who joined later were Joey Clement (replaced later by Monty Anderson) on bass guitar, and Kyle Peek on drums and backing vocals.

The Declaration Tour began on February 13, 2009, in Tallahassee, Florida, and was originally set to end in Tulsa, Oklahoma, on April 25, 2009.

The tour however was extended twice – the first time through May 31, 2009, and then again starting from June 18, 2009, in Del Mar, California, and finally ending December 1, 2009, in Charlotte, North Carolina, after a total of 153 shows.

He had been collaborating with Raine Maida and Chantal Kreviazuk, Matt Squire, Gregg Wattenberg, John Rzeznik, Sam Hollander and Dave Katz, Claude Kelly, Brian Howes, David Hodges, Tommy Henriksen, Steven Van Zandt, Kevin Griffin, Zac Maloy, Ryan Tedder, Jim Irvin, Jamie Houston, Ryan Star & Julian Emery and Max Martin.

[67] Before the performance, Cook confirmed to Shirley Halperin of the Hollywood Reporter that he was without a recording contract, having departed from RCA, and was self-releasing "The Last Song I'll Write for You".

Cook co-penned country music singer David Nail's 2014 single, "Kiss You Tonight" from his album I'm a Fire.

[73] He worked with previous songwriters like Zac Maloy, Kevin Griffin, David Hodges, and Andy Skib (who also contributed as engineer).

Cook also collaborated with Jerry Flowers, Earth to Andy members Andy Waldeck and Chris Reardon (with Reardon also serving as co-producer on one track – "Laying Me Low"), local Nashville writers Blair Daly and Chad Carlson, former bandmate Devin Bronson, and Steven Miller.

The first half of the tour, with opening act Andrew Ripp, consisted of 33 shows in 24 states, beginning on September 30, 2015, in Phoenix, Arizona, and ending on November 21, 2015, in Tulsa, Oklahoma.

[77] On March 27, 2017, Cook teased a thirty-second clip on social media with the quote "#gimmeheartbreak", indicating his new single, "Gimme Heartbreak" would be released on June 23, 2017.

[89] During an episode of The Rich Redmond Show in February 2020, Cook was originally set to appear in the sitcom 2 Broke Girls; however the series was later cancelled.

[92] On May 3, 2009, at the "Race for Hope" in Washington, D.C., Cook announced the death of his brother during the awards speech, and stated that he "couldn't imagine being anywhere else right now."

[94] Cook appeared at the 2008 Glamour magazine Women of the Year Awards as a guest of Mary Steenburgen to surprise honoree Hillary Clinton, a fan of American Idol.

[95] Cook appeared in several promotions for the November 1, 2008, episode of Saturday Night Live, hosted by Ben Affleck.

On August 11, 2009, Cook performed "Starseed" with Canadian alternative rock band, Our Lady Peace at the House of Blues in Dallas, Texas.

[100] On August 7, 2009, Cook performed the Fleetwood Mac hit "Little Lies" with American Idol season 8 winner Kris Allen and runner-up Adam Lambert on ABC's Good Morning America's Summer Concert Series in Central Park.

On May 20, 2009, Cook performed "Permanent" during the finale of eighth season in honor of his late brother Adam, where proceeds from the live single went to Accelerate Brain Cancer Cure (ABC2).

During the March 17, 2010, episode of American Idol, Cook sang the Rolling Stones song "Jumpin' Jack Flash".

In May 2008, Cook asked Season 2 American Idol alum and TV Guide Network correspondent Kimberly Caldwell for a dinner date while on the red carpet before the show's seventh-season finale.

"[105] In a November 2008 interview with People magazine, Cook said his relationship with Caldwell was a "nice break from the chaos" of post-Idol fame.

[111] Immediately after winning American Idol, Cook was asked backstage by Entertainment Weekly who his top five favorite bands were.