Charley Johnson's cause of death: How did Broncos' Ring of Fame QB die?

Former Denver Broncos quarterback Charley Johnson died on Tuesday at age 85. His alma mater, New Mexico State, announced the news.

The Aggies didn't list his cause of death. Johnson became a college legend after leading New Mexico State to 19 wins in two seasons. He also earned consecutive Sun Bowl victories, receiving MVP honors in 1959 and 1960.

Johnson joined the NFL as the St. Louis Cardinals' No. 109 pick in the 1960 NFL Draft. He would spend his pro career with the Cardinals, Houston Oilers and Denver Broncos while racking up 1,737 completions for 170 touchdowns and 24,410 passing yards.

Johnson was integral to the Denver Broncos' first winning season, guiding them to a 7-5-2 mark in 1973. After that milestone, his teammates named him as their most valuable offensive player, and he earned All-AFC Honors.

His tenure with the Broncos ended with 7,238 passing yards and 52 touchdown passes.

Charley Johnson entered the Broncos' Ring of Fame in 1986. He joined Frank Tripucka, Craig Morton, John Elway and Peyton Manning as the only quarterbacks in that club.

Charley Johnson was much more than a football player

Besides being an NFL play-caller, Charley Johnson served in the Reserve Officers' Training Corps (ROTC), being called into active duty in 1967. At the time, he was an NFL player. He also served in the U.S. Army Reserves and worked for NASA while on the Cardinal's roster.

Johnson was head of NMSU's chemical engineering department from 2000 to 2004 and returned to the football program in 2010 as the Aggies' interim coach.

Johnson was inducted into the Texas Sports Hall of Fame in 2010 and the New Mexico Sports Hall of Fame in 2008. He was a Big Spring, Texas native.

The Denver Broncos didn't gain widespread attention until John Elway came along. However, Charley Johnson made an early impact on the team, showing they could compete even when the odds weren't in their favor.