He was named an All-State player by the Chicago Tribune and was selected to play in the first East-West All-America Football Game in January 2007.

In 2011, Molk anchored a line that led the way for Denard Robinson and Fitzgerald Toussaint to become Michigan's first duo of 1,000-yard rushers since 1975.

[15] However, he endured a serious undisclosed illness that caused him to lose 15 pounds (6.8 kg) and found himself in a battle with redshirt junior David Moosman to be the starting center.

[22] Molk injured his toe at the end Little Brown Jug game against Minnesota of the November 8, 2008, but he was fine the following week.

[28] Molk suffered a broken foot in the third game of the season as the 2009 Wolverines pushed their record to 3–0 and had surgery two days later.

[30] However, during the subsequent game against Penn State on October 24, he tore knee ligaments and was lost for the season as well as spring football.

[31] As a redshirt junior, he was selected to the 2010 preseason Rimington Trophy watchlist for the 2010 Michigan Wolverines football team and later a finalist after the regular season had concluded.

[32][33] That season Denard Robinson established numerous quarterback rushing records lining up behind and often running behind Molk.

He broke Drew Brees' Big Ten single-season total offense record of 4,189 yards.

[56] Molk was one of 54 offensive linemen, and the fourth-ranked center—behind Peter Konz, Garth Gerhart, and Ben Jones[57]—, that participated in the 2012 NFL Scouting Combine.

[59] His 41 reps in the bench press ranked first among offensive linemen and second at the entire combine, behind only nose tackle Dontari Poe.

[68] He played 12 games for the 2012 San Diego Chargers, mostly on special teams and as an extra lineman in short yardage situations, before being placed on injured reserve on December 4, 2012.

[73] David Molk lives outside Chicago in Lemont, Illinois, with his widowed father, his mother having died from breast cancer when he was 12.

[74][75] After the controversial semi-autobiographical book NFL Confidential: True Confessions from the Gutter of Football was released in 2016, multiple Redditors guessed the unknown author, nicknamed "Johnny Anonymous" in the book, was actually Molk due to the similarities between the narrator's experiences and the 2014 Philadelphia Eagles season, when Molk had been a backup center with the team.