Question: The 1972 Stanford Cardinals football team represented Stanford University in the 1972 college football season, which American football player and defensive coordinator, became Stanford's new head coach?

Context paragraphs:
1980 Stanford Cardinals football team: The 1980 Stanford Cardinals football team represented Stanford University in the 1980 NCAA Division I-A football season.  Following the surprise resignation of Rod Dowhower, Stanford's new head coach was Paul Wiggin, a former star defensive end at Stanford who had also played 10 years in the NFL and most recently had been an assistant coach in the NFL.

1976 Stanford Cardinals football team: The 1976 Stanford Cardinals football team represented Stanford University in the 1976 NCAA Division I football season.  They were led by head coach Jack Christiansen.  After a disappointing season, Christiansen was fired before the last game of the season, the Big Game versus Cal; Christiansen coached that final game, which Stanford rallied to win in the final two minutes.

1979 Stanford Cardinals football team: The 1979 Stanford Cardinals football team represented Stanford University during the 1979 NCAA Division I-A football season.  Rod Dowhower, an assistant coach under previous coach Bill Walsh, was hired as Stanford's new head coach, but resigned after the season to take an assistant coaching position with the NFL's Denver Broncos.

1975 Stanford Cardinals football team: The 1975 Stanford Cardinals football team represented Stanford University during the 1975 NCAA Division I football season.  They were coached by fourth-year head coach Jack Christiansen.

1981 Stanford Cardinals football team: The 1981 Stanford Cardinals football team represented Stanford University in the 1981 NCAA Division I-A football season.  From 1972 until November 17, 1981, Stanford’s official nickname was Cardinals, in reference to one of the school colors, not the bird.  After 1981 the team was referred to as the singular "Cardinal".

2011 Stanford Cardinal football team: The 2011 Stanford Cardinal football team represented Stanford University in the 2011 NCAA Division I FBS college football season.  The Cardinal were led by former offensive coordinator and new head coach David Shaw, as Jim Harbaugh departed following the 2010 season in order to become the head coach of the San Francisco 49ers.  They played their home games at Stanford Stadium and are members of the North Division of the Pac-12 Conference.  They finished the season with 11–2 in overall record, 8–1 in Pac-12 play to finish in a tie with Oregon for first place in the North Division.  Due to their head-to-head loss to Oregon, they did not represent the division in the inaugural Pac-12 Football Championship Game.  They were invited the Fiesta Bowl, their second consecutive BCS game, where they were defeated by Oklahoma State 38–41 in overtime.

1972 Stanford Cardinals football team: The 1972 Stanford Cardinals football team represented Stanford University in the 1972 college football season.  Following the departure of head coach John Ralston the previous year, defensive coordinator Jack Christiansen became Stanford's new head coach.

Jack Christiansen: John LeRoy Christiansen (December 20, 1928 – June 29, 1986) was an American football player and coach.  He played professional football in the National Football League (NFL) for the Detroit Lions as a defensive back and return specialist from 1951 to 1958.  He helped lead the Lions to three NFL championships in 1952, 1953, and 1957 and was a first-team All-NFL player in six of his eight years in the league.  He led the NFL in interceptions in 1953 and 1957 and in punt returns for touchdown in 1951, 1952, 1954, and 1956.  His eight career punt returns for touchdowns was an NFL record until 1989 and remains the fourth best in league history.  He was inducted into the Pro Football Hall of Fame in 1970.

1977 Stanford Cardinals football team: The 1977 Stanford Cardinals football team represented Stanford University during the 1977 NCAA Division I football season.  Bill Walsh served his first season as Stanford's head coach.  The Cardinals were led by senior quarterback Guy Benjamin, who won the Sammy Baugh Trophy, awarded to the best passer in college football; senior receiver James Lofton, who caught 57 passes for 1,010 yards and 14 TDs and was named an AP and NEA Second Team All-American; junior linebacker Gordy Ceresino, and freshman running back Darrin Nelson.

1978 Stanford Cardinals football team: The 1978 Stanford Cardinals football team represented Stanford University during the 1978 NCAA Division I-A football season.  Bill Walsh served the second and final season of his first stint as Stanford's head coach.

Supporting paragraphs: 1972 Stanford Cardinals football team Jack Christiansen
Answer: Jack Christiansen