The Birmingham-born driver will hence make his debut as a Formula E driver next season, which kicks off in Mexico on 14 January, with the incoming Nissan-powered team.
Hughes has spent the past two seasons as Mercedes' reserve driver in support of Stoffel Vandoorne and Nyck de Vries, and remains with the squad in its transition to McLaren.
He had earlier vacated his Van Amersfoort Racing seat in Formula 2, citing a desire to focus on his Formula E aspirations, having joined the Dutch team at the start of 2022 for its first year in the F1 feeder category.
This was preceded by a spell with HWA in F2, and Hughes had also raced with the German squad for two seasons in F3, finishing seventh in the championship on both occasions.
"First and foremost, I'm very proud and feel very privileged to become part of the McLaren Racing family, being given the chance to represent such a prestigious brand," said Hughes.
"Growing up, McLaren was one of the teams that inspired me to start racing. To now go full circle, representing the team myself in Formula E feels incredible.
I've obviously been with the Formula E team in a different guise before and we have already achieved great results. It's good to have that relationship and I know what's expected of me."
"Coming in at a time where a new generation car is introduced in the series excites me. It feels like a good opportunity and chance, especially being a rookie in Season 9. It's set to be a great year and I can't wait to kick off the journey ahead!"
"Today's announcement feels like a long time coming," added McLaren team principal Ian James.
"Since May this year, when we first announced McLaren Racing's entry into Formula E, we have been working tirelessly to get in place the best possible team and structure for sustainable success.
"I'm excited to work together with Rene and Jake this upcoming season. They are both incredibly talented people, and I think they will both bring something different to the mix.
"Jake is an exciting talent, who we have worked with before as our Reserve and Development driver. Over the years, the team and Jake have built a relationship, and that, combined with his sheer talent, will be what can give us an edge going into this season.
"We've given Jake a chance to prove himself on the big stage in Season 9, and his story is a perfect example of the talent development that we believe in as a team."
The team has moved out of the Mercedes High Performance Powertrains base in Brixworth to a facility at Bicester Heritage, from where McLaren will prepare for its first season in the championship in its new guise.
It has also enlisted Neom as a title sponsor, with the Saudi Arabian Public Investment Fund seeking to promote the planned 'smart city' currently under construction on the coast of the Red Sea.
