In the fall of 1987, a package arrived on the desk of Laurence H. Tribe, a Harvard law professor who had just lost a Supreme Court case on gay rights. It contained the legal opinions of Anthony M. Kennedy, a strait-laced, conservative Republican jurist from Sacramento who hardly seemed sympathetic to that cause.

The package was sent by one of the most influential men in the California capital then, Gordon Schaber, a law school dean who had enlisted a young Mr. Kennedy to teach night classes and nurtured his career. Now Mr. Schaber was angling for President Ronald Reagan to elevate his friend to the Supreme Court — and he wanted the Harvard professor’s support.

“Gordon Schaber said that Tony Kennedy was entirely comfortable with gay friends,” said Professor Tribe, who later testified to urge the Senate to confirm Justice Kennedy. “He said he never regarded them as inferior in any way or as people who should be ostracized, and I did think that was a good signal of where he was on these matters.”

Now, as the Supreme Court prepares to rule on whether to grant a constitutional right to same-sex marriage, Justice Kennedy, a onetime altar boy, has emerged as an unlikely gay rights icon. At 78, he has advanced legal equality for gays more than any other American jurist, making his friend Mr. Schaber, who died in 1997 — and who was, many who knew him believe, a closeted gay man — look prescient.