The move comes just four weeks before the new Premier League season begins and brings an end to Howe's five-year spell on Tyneside, one that delivered the club's first major domestic trophy in 70 years when they won the Carabao Cup in 2025, along with Champions League qualification in both 2023 and 2025,.
It comes after a difficult follow-up campaign in which Newcastle United finished 12th in the Premier League, losing 17 of their 38 matches, were knocked out of the Champions League last 16 by Barcelona, and exited the EFL Cup at the semi-final stage. His final game in charge was Wednesday's 4-1 pre-season friendly defeat at Bristol City.
Howe is understood to have told the Newcastle hierarchy of his intention to leave around a fortnight ago, having initially decided earlier this year to stay on despite the inevitability of player sales, reports BBC Sport.
The club asked him to reconsider, which he did, before eventually accepting his wishes on the condition he remained in place while a successor was identified — a request he agreed to.
Sources close to the situation say Howe does not have another job lined up and that the decision is purely down to a sense that his time at the club had run its course; he is said to be deeply emotional about leaving but had been considering it for several months, and intends to take a break from the game before deciding on his next move.
Frustration over the club's transfer business is understood to have been a contributing factor, though not the only one. Howe was left unhappy by the sale of Alexander Isak to Liverpool last year, despite the club spending around £240m on new arrivals in the same window, and has since lost Sandro Tonali to Tottenham and Anthony Gordon to Barcelona this summer, while Arsenal continue to pursue captain Bruno Guimarães. Howe had previously been linked with both the England job and Manchester United in recent years amid the stability he built at St James' Park.
Howe leaves with a Newcastle managerial record of 84 wins from 179 Premier League games, more than any other manager in the club's history, and a win percentage of 46.9%, bettered at the club only by Kevin Keegan.
Jaissle, 38, joined Al-Ahli in 2023 and has led the Saudi club to back-to-back AFC Champions League titles. A German centre-back capped at Under-21 level, he was forced to retire at 25 through injury having come through Stuttgart's academy and played for Hoffenheim between 2007 and 2014.
He moved into coaching as Brøndby assistant, took charge of Austrian second-tier side Liefering, then succeeded Jesse Marsch at Red Bull Salzburg in 2021, winning back-to-back Austrian Bundesliga titles and the Austrian Cup before his move to Saudi Arabia.