The 27-year-old, who has signed a three-year deal with the Magpies, becomes Rafa Benitez's sixth signing of the summer and will bolster Newcastle's attacking options after moves for Arsenal's Lucas Perez and former Malaga striker Sandro Ramirez were thwarted by a salary structure which sees the club unwilling to offer more than £70,000-a-week.
The former Spain Under-21 international, spent last season on loan at Deportivo La Coruna in Spain, scoring six goals in 24 league appearances.
"I feel very happy, because I have signed for a very big club. I'm very happy to be part of this club, and so excited," said Joselu.
"I'm looking forward to getting to know my teammates, the city, the training ground, the stadium and all the supporters. I'm very happy to be here."
Having come through the ranks at Celta Vigo, Joselu joined Real Madrid in 2009, before moving to the Bundesliga with Hoffenheim, Eintracht Frankfurt and Hannover 96, from which he joined Stoke in June 2015 for £5.75m.
Following his move to the Potters, however, he struggled to adapt to the demands of the Premier League and scored just four goals in 27 games in his only season in the English top-flight.
However, Benitez believes Joselu's brief taste of top flight football in England could help him hit the ground running at St James' Park.
"Obviously he has experience of English football and the Premier League. We think if we can exploit his full potential he will be a good signing for us," said the Newcastle manager.
"He knows and accepts the challenge we've given him at Newcastle and he's keen to come and fight for a position in the team."
Throughout the summer, Benitez has reiterated the need for more signings, hinting the club had not strengthened adequately, despite splashing a combined £20m on the likes of Jacob Murphy from Norwich City and former Eibar man Florian Lejeune.
Newcastle marked their return to the Premier League with a 2-0 defeat at home against Tottenham Hotspur on Sunday (13 August) and travel to fellow newly-promoted side Huddersfield Town this weekend.