Complex sentence: His on-field career at Colorado was mostly successful; however, his reputation was tarnished by a recruiting scandal, insensitive off-field remarks and failure to maintain the on-field success of his predecessors.
Split into simpler sentences: His on-field career at Colorado was mostly successful. However, his reputation was tarnished by a recruiting scandal, insensitive off-field remarks and failure to maintain the on-field success of his predecessors.