Complex sentence: He was named interim head football coach of the Cougars, after Kevin Sumlin left for Texas A&M, and shortly thereafter was named the Cougars' next Head Coach on December 21,2011.
Split into simpler sentences: He was named interim head football coach of the Cougars, after Kevin Sumlin left for Texas A&M. Shortly thereafter, he was named the Cougars' Head Coach on December 21,2011.