An engineering major at NMSU , Johnson continued his academic pursuits during his NFL career and obtained master 's and doctoral degrees in chemical engineering from Washington University in St. Louis while concurrently playing in the NFL .
An engineering major at NMSU , Johnson obtained his bachelor 's degree in chemical engineering at NMSU with a 4.0 GPA in 1961 . 
 Johnson then continued his academic pursuits during his NFL career and obtained master 's and doctoral degrees in chemical engineering from Washington University in St. Louis while concurrently playing in the NFL .