"I feel very exhausted and want to take a break from football management".
Moyes, by contrast, has won 20 of his last 85 games in management with Sunderland and Real Sociedad - West Ham owners David Gold and David Sullivan will be hoping his time at Preston, Everton and Manchester United is more representative.
According to the BBC, the Scot's two-and-a-half year deal with the club contains a break clause which will allow them to part ways if needed at the end of the season.
Moyes had managed in the Premier League for 14 seasons and led Everton FC to the UEFA Champions League, Europa League and an FA Cup final.More news: United States resumes 'limited' visa services to Turkish citizens
As impressive as Moyes' 11-year stint at Everton was - with nine top-eight finishes and having guided the club into the UEFA Champions League qualifiers in 2005 - he knows he can not dine out on that forever.
West Ham went for Moyes because higher-profile candidates like Carlo Ancelotti, Rafa Benitez and Guus Hiddink did not fancy the job. "I've got no doubts about that, but ultimately we have to show it on the pitch", he added.
Moyes was sacked less than a season into a six-year contract and is still searching for the chance to rebuild his reputation.
It was an ill-fated venture, with the 34-year-old looking well past his best and making only three appearances for West Ham.More news: Could Disney/Fox Talks Give Marvel X-Men & Fantastic Four Back?
Joint-Chairman David Sullivan said Moyes was the right man for the job.
"He is highly regarded and respected within the game, and will bring fresh ideas, organisation and enthusiasm".
Moyes' first match in charge will come after the worldwide break, a trip to Watford in the Premier League on November 19.
"He proved with Everton that he has great qualities and we feel that West Ham United is a club that will give David the platform to display those qualities again".More news: Trump says he'll meet Putin to talk North Korea