A man whose sentence of 365 weekend days in jail in the killing of his former girlfriend was both hailed as boldly innovative and denounced as a too lenient disgrace has resigned from his job as a civilian systems analyst for the Army.

The resignation of Edward Strother came to light yesterday, almost three months after the conservative Washington Legal Foundation wrote to the Army in behalf of his victim's mother urging that Strother be fired.

It was not immediately clear what effect Strother's action, described by the Army as a request for voluntary retirement, would have on his ability to carry out another part of the sentence: the payment of monthly restitution to his victim's 6-year-old daughter.

Strother, who was 54 and an Oxon Hill resident at the time of his Feb. 15 sentencing, had pleaded guilty to a charge of second-degree murder in the March 1984 shooting death of Carol R. Gray in her District home.

Police charged that he shot Gray, 33, three times in the head while her 80-year-old grandmother watched. He has said he could not remember the shooting.

The motivation and timing of Strother's decision to resign were not clear last night. In a letter released yesterday by the legal foundation, an Army official wrote that Strother "had elected to leave government service voluntarily prior to his conviction and sentencing."

The letter from Assistant Secretary of the Army Delbert L. Spurlock Jr. to Paul D. Kamenar, an official of the legal foundation, said the date of Strother's "intended retirement" is July 30.

In a news release issued yesterday, the foundation said Strother's departure from the Army "was in response" to the foundation's May 6 request in behalf of the victim's mother, Eyvonne Gray.

Despite the wording of Spurlock's letter, Strother's attorney asserted in an interview last night that the foundation and Eyvonne Gray "have succeeded in some measure in getting him terminated" and expressed the belief that the decision to retire was influenced by their pressure.

"He basically indicated that" because of the requests for his dismissal "he felt it would be better to seek retirement," said the lawyer, Robert J. Pleshaw.

A government employe for more than 30 years, Strother "was hoping to stay a little longer," said the lawyer. Strother could not be reached for comment.

Spurlock, contacted last night, said he "would have to check the record" to clear up the question of when retirement was first sought.

Spurlock's letter said action is under way to dismiss Strother from the Army reserve, in which he holds the rank of sergeant first class. An army spokesman said a felony conviction can bring dismissal.

Pleshaw said that leaving government service might make it more difficult for Strother to pay the court-ordered restitution. By failing to do so, Pleshaw said, he might be held in violation of probation conditions and possibly ordered to serve the 14- to 45-year sentence, most of which was suspended. Strother's salary was said to be about $28,000.

Kamenar, executive legal director of the Washington legal foundation, which describes itself as a public interest law center that advocates crime victims' rights, could not be reached last night.

Previously, he has said that he was not seeking to have Strother imprisoned, but "if that does happen, no tears will be shed."