The 59-year-old Northern Irishman, who has signed a three-year contract, had been out of the game since leaving Aston Villa at the start of last season.
He takes over with the club sitting 16th in the 20-team table, with 11 points from 13 games.
Bruce initially brought Elmohamady from Egyptian side ENPPI on a season-long loan in the summer of 2010.
The Egyptian international impressed in his maiden season in the elite Premier League to earn a permanent stay at Sunderland in the close of season, but he is struggling to maintain his regular place in the team’s starting line-up this term.
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