I thoroughly enjoyed watching his cameo in Clint Eastwoods' "Honky Tonk Man." That's one movie I went to see--not knowing much about it--and got more than my money's worth. Marty Robbins was one of the reasons, too. I don't know anything about his personality or lack of one, but appreciated his unique contribution to music.
Marty seemed to know he was short on time due to his history of heart disease, he died after bypass surgery and that came after several heart attacks. Yet he managed to have a second career as a NASCAR driver and did well, had several top 10 finishes.
He had a number of crossover hits, most came early in his career, e.g. Stairway of Love, A White Sport Coat and a Pink Carnation.