The 38-year-old arrives on Tyneside after leading Al-Ahli to back-to-back AFC Champions League titles, with Newcastle paying compensation in excess of £9m to the Saudi club to complete the move.
He succeeds Eddie Howe, who left St James' Park after five years in charge that yielded the club's first major trophy since 1969 but ended with Newcastle finishing 12th in the Premier League last season.
Jaissle made his name at Red Bull Salzburg, taking charge at just 33 and winning a domestic double in his first season before reaching the Champions League knockout stages for the first time in the Austrian club's history.
His playing career, spent largely at Hoffenheim, ended prematurely through injury when he was 25, prompting a switch into coaching that began in Denmark and an academy role at Salzburg before his first senior post at FC Liefering.
Newcastle chief executive David Hopkinson said: "His track record of success, leadership qualities and relentless drive to improve make him an exceptional fit for Newcastle United.
"We believe he is the right person to lead the club into the next phase of our journey."
Sporting director Ross Wilson pointed to the impression Jaissle left during the recruitment process, saying: "His teams play high-energy football and we could feel his passion during all of our discussions throughout the recruitment process."
Jaissle described the move as "an incredible honour", saying he had followed Newcastle's progress closely and had been struck by the scale of the club's ambition.
"When Newcastle United comes your way, you take notice," he said. "I fully and unreservedly believe in this project, the ambition and the direction the club is taking. My teams are built on togetherness, hard work, intensity and a passion to improve every single day. I will bring full commitment, full energy and a determination to give everything I have to help this club achieve its ambitions."
Jaissle has signed a four-year deal and has already been working with his new squad, having joined the players at their pre-season training camp in Spain over the weekend.
His backroom staff are expected to be confirmed shortly, with his first match in charge due to be a pre-season friendly away to Valencia this weekend, just 18 days before Newcastle open their Premier League campaign at home to Liverpool.