Lawyers for Anthony D. Weiner, the former Democratic congressman whose lewd text exchanges with a teenage girl led to his prosecution and embroiled him in an F.B.I. investigation of Hillary Clinton before the presidential election, asked a judge on Wednesday night to spare him a prison sentence.

In asking that Mr. Weiner receive probation, his lawyers described his behavior as “inexcusable,” but cited his “remarkable progress” over the past year.

Mr. Weiner, 53, writing separately to the judge, cited his “profound” regret for endangering the well-being of the girl, whom he understood to be 15.

He added, “My continued acting out over years crushed the aspirations of my wife and ruined our marriage.” And, he said, his young son “will forever have to answer questions about the public and private failings of his father.”