The 57-year-old has put pen to paper on a two-year contract with an option of a third, and he will officially begin work with the Hammers on 1 July.
Lopetegui brings a wealth of coaching experience to the London Stadium having previously managed Porto, Real Madrid, Spain and Sevilla, winning the Europa League with the latter in 2020.
The Spaniard, who was most recently in charge of Wolverhampton Wanderers during the second half of 2022-23, claims he is 'where he wants to be' and intends to "make a big, big noise" as he endeavours to take West Ham to the next level.
Before officially taking the reins later this summer, Lopetegui is set to assess his current first-team squad and holds talks with the club's hierarchy over the key areas in which he would like to strengthen ahead of the new season.
With that in mind, Sports Mole takes a look at six players who West Ham could look to sign under Lopetegui.
Max Kilman - Wolves
After conceding 74 goals in the Premier League in 2023-24, West Ham are expected to bolster their options in central defence this summer and one name who is known to be admired by Lopetegui is Wolves captain Max Kilman.
The Sun reports that the Hammers are set to revive their interest in the 27-year-old, who made 24 appearances under Lopetegui during his brief stint at Molineux.
In order to comply with the Premier League's Profit and Sustainability Rules as well as generate funds for new signings, Wolves will likely be required to sell at least one of their key players this summer, but they could demand as much as £45m for Kilman.
The Englishman has been ever-present in Wolves' backline this term, playing the full 90 minutes in all 38 Premier League games, while he has made a total of 151 appearances in all competitions since making his senior debut in 2019.
Fabricio Bruno - Flamengo
Kilman is not the only central defender said to be on West Ham's radar as they have also been linked with a move for 28-year-old Fabricio Bruno in recent weeks.
According to journalist Fabrizio Romano, via ExWHUEmployee, West Ham are in advanced talks to sign Bruno from Flamengo and progress has been made in negotiations between both parties.
The 6ft 4in centre-back is said to have already agree personal terms over a move to the Hammers and sporting director Tim Steidten is working hard behind the scenes to get the deal over the line.
Bruno, who has spent his entire club career in his native Brazil, has excelled for current club Flamengo since joining in 2022, making 114 appearances in all competitions, and he was recently rewarded with his first international cap for Brazil when they faced England in a friendly at Wembley Stadium in March.
Wesley Gassova - Corinthians
Another Brazilian on West Ham's radar is 19-year-old Wesley Gassova, who has made a notable impression in his homeland with Corinthians since bursting onto the scene in April 2022.
It was reported earlier this month by the Evening Standard that West Ham have opened talks to sign Gassova, who is valued in the region of £26m, although the Hammers hope to strike a deal at closer to £15m.
West Ham could face stern competition for Gassova, though, as Liverpool, Fulham, Everton, Atletico Madrid and Real Betis are among the clubs said to be interested in the skillful winger, who is considered one of the most exciting young prospects in Brazil.
Youssef En-Nesyri - Sevilla
Youssef En-Nesyri has been a long-term target for West Ham and they could now look to step up their pursuit of the striker now that Lopetegui has arrived at the club.
During his time as Sevilla manager, Lopetegui signed En-Nesyri in January 2020 and the 26-year-old quickly cemented his place in the first team, helping the Spanish side win the Europa League and secure a top-four finish in La Liga.
En-Nesyri, who was part of the Morocco team that reached the 2022 World Cup semi-finals, has since made 195 appearances for Sevilla in all competitions, scoring 72 goals, including 19 strikes in 40 games during the 2023-24 campaign.
The 26-year-old will soon be entering the final 12 months of his contract at Sevilla and he has been tipped to test himself in the Premier League with West Ham, who are said to be in the market for a new striker amid uncertainty over the futures of Michail Antonio and Danny Ings.
Marcos Acuna - Sevilla
Lopetegui could also raid his former club Sevilla for another experiences player in the form of 32-year-old left-back Marcos Acuna.
The Sun reports that Acuna is being considered as a possible new signing by the Hammers, who are set to part ways with 34-year-old Aaron Cresswell when his contract expires in June.
It is thought that Sevilla are open to letting Acuna, one of the club's highest earner, leave this summer now that he has just a year left on his deal, and the experienced defender could be available for a cut-price fee.
Acuna, who has made almost 150 appearances for Sevilla and won the 2022 World Cup wit Argentina, has also attracted interest from Unai Emery's Aston Villa.
Serhou Guirassy - Stuttgart
Stuttgart talisman Serhou Guirassy has emerged as one of the most in-demand strikers in Europe ahead of the summer transfer window and West Ham are believed to have stepped up their interest in the 28-year-old in a bid to move to the front of the queue for his signature.
According to the Evening Standard, the Hammers are considering a summer swoop Guirassy, who has a release clause in his Stuttgart contract of just £15m, which has understandably alerted a number of clubs.
Steitden is said to be a long-time admirer of Guirassy, who is expected to leave Stuttgart this summer even though they have qualified for next season's Champions League.
Guinea international Guirassy, who has also been linked with Manchester United, only joined Stuttgart on a permanent basis last summer following a successful loan spell from FC Koln, and scored 28 goals in as many Bundesliga matches to propel Die Roten up to second place, finishing the 2023-24 season above Bayern Munich in third.