On April 1, 2016, DeLeone was promoted to the Kansas City Chiefs assistant linebackers coach.[1] The Chiefs went 12–4 in 2016 and clinched the AFC West title for the first time since 2010 and made the playoffs for the second year in a row for the first time since 1995.[2][3] They would lose in the Divisional Round against the Pittsburgh Steelers 16–18.[4] During the season they would defeat the NFC Champions, the Atlanta Falcons 29-28.[5] Linebackers Justin Houston, Derrick Johnson, and Tamba Hali would make the NFL's Top 100, ranked 26th, 80th, and 84th respectively.
The Chiefs went 10–6 in 2017 and won back-to-back AFC West titles for the first time in franchise history and made the playoffs for the third year in a row for the first time since 1994.[6] They would lose to the Tennessee Titans in the Wild Card round 21-22.[7] They would defeat both the AFC champion New England Patriots and the NFC champion Philadelphia Eagles during the season.[8][9] Under his coaching, Justin Houston would rank 7th in tackles for loss.[10] Justin Houston would make the NFL's Top 100 ranked 76th.
In the 2017 offseason, Derrick Johnson left in free agency & Tamba Hali was released.[11][12] On January 29, 2018, DeLeone was promoted to the Kansas City Chiefs inside linebackers coach.[13] The Chiefs went 12-4 and won their third straight AFC West title in franchise history and made the playoffs for the fourth year in a row for the first time since 1993.[14][15] They would go on to defeat the Indianapolis Colts in the Divisional Round 31-13 and then lose to the New England Patriots in the AFC Championship game 31–37.[16][17] During the season they defeated two playoff teams; the AFC North champion Baltimore Ravens and the Los Angeles Chargers.[18][19] Under his coaching, Justin Houston ranked 5th in forced fumbles and linebacker Reggie Ragland recorded the 8th longest interception return.[20] At the end of the season, defensive coordinator Bob Sutton was fired and DeLeone left to join his former offensive coordinator Matt Nagy.[21]
Chicago Bears
On January 29, 2019, the Chicago Bears named DeLeone the inside linebackers coach.[22] The Bears went 8-8 in 2019 and missed the playoffs.[23]
Detroit Lions
In January 2021, the Detroit Lions hired DeLeone as their inside linebacker coach.[24] In February 2022, the Lions parted ways with DeLeone after one season.[25]
Kansas Jayhawks
In the spring of 2022, DeLeone was hired as a defensive analyst at Kansas.[26]
Personal life
Mark graduated from the University of Iowa, earning a bachelor's degree in liberal arts & sciences. He is the son of the late George DeLeone, who was an assistant coach in college football and the NFL for nearly 50 years.
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