Rob Ryan Rob Ryan ( born December 13 , 1962 ) is the defensive coordinator for the Dallas Cowboys of the National Football League . He is the son of former defensive coordinator and head coach Buddy Ryan and the twin brother of current head coach of the New York Jets , Rex Ryan . Early life . When his parents , Doris and Buddy Ryan , divorced in 1966 , Rob and his fraternal twin , Rex , moved with Doris to Toronto . In 1974 , they moved back to the United States to live with their father . He attended Stevenson High School in Lincolnshire , Illinois . Playing career . Ryan played defensive end opposite his brother Rex at Southwestern Oklahoma State University . Coaching career . Ryan was a graduate assistant at Western Kentucky in 1987 and at Ohio State in 1988 . Ryan then spent 5 seasons at Tennessee State , where he coached running backs ( 1989 – 91 ) , wide receivers ( 1992 ) and the defensive line ( 1993 ) . He served as defensive coordinator at Hutchinson Community College in 1996 , where they led the nation in total defense ( 228 yards per game ) and in sacks ( 56 ) . His defense also set a national record by forcing 49 turnovers . Ryan originally entered the NFL coaching ranks in 1994 as defensive backs coach on his father ' s staff at Arizona Cardinals . He also coached Cardinals cornerbacks and safeties in 1995 . With Ryan as his position coach , cornerback Aeneas Williams earned two trips to the Pro Bowl in 1994 and 1995 . In 1995 , the Cardinals led the NFL with 32 interceptions and 42 total takeaways . The 1994 Cardinals ranked second in the NFL total defense , second in run defense and third in pass defense . From 1997 – 99 , Ryan was the defensive coordinator at Oklahoma State , where the Cowboys defense continually ranked among the best in the nation , also he was named Coordinator of the Year by The Sporting News in 1997 . In 1999 , they were ranked 10th in the nation in total defense . In 1998 , they were second in the nation with 41 sacks . In his first season at Oklahoma State , the Cowboys defense finished among the nation top - 20 in turnover margin , rushing defense , scoring defense and total defense , allowing just 302 . 7 yards per game . It was an over 100 - yard improvement per game from the year before and helped the Cowboys produce an 8 – 4 mark and capping the 1997 season with a berth in the Alamo Bowl . From 2000 to 2003 , Ryan was the linebackers coach for the New England Patriots . In 2003 , the Patriots ranked first in the NFL in fewest points allowed 238 while ranking seventh overall in the NFL in total defense . Ryan ' s unit also contributed to one of the best scoring defenses in franchise history in 2001 , as the Patriots allowed just 17 points per game and produced Pro Bowlers Willie McGinest and Tedy Bruschi . From 2004 to 2008 , Ryan was the defensive coordinator for the Oakland Raiders . In 2006 , the Raiders ranked third in yards allowed per game and eighteenth in points allowed per game . Former Cleveland Browns head coach Eric Mangini named Ryan as defensive coordinator on January 14 , 2009 . He was officially named the Dallas Cowboys defensive coordinator on January 19 , 2011 . Personal life . Ryan and his wife Kristin have three children : sons Joseph and Matthew and daughter Dimitra .