A dark, handsome, sensitive leading actor of television who, after off-Broadway and TV experience, gained some attention amid stiff competition for his recurring role on two seasons of NBC's "Hill Street Blues". Olin was subsequently saddled with an archetypal soap opera role on CBS' "Falcon Crest" (to which, to his credit, he brought a certain low-keyed conviction): a priest who has a torrid affair with one of his parishioners. It was not until his fourth TV series, the acclaimed ABC drama "thirtysomething", that Olin really found a role that properly showcased his casual sincerity and charm,