The Ghana international had his mother and two brothers fly from Ghana to East London to partake in the ceremony.
Kudus has penned a five-year contract to join the Hammers from Dutch side Ajax for an undisclosed fee.
He has been one of the sought-after player in Europe after after impressing with 18 goals and seven assists in all competitions last season.
Kudus becomes the club’s fourth major summer signing after Edson Álvarez, Dinos Mavropanos and James Ward-Prowse.
Manager David Moyes said: “I’m delighted we’ve been able to bring Mohammed to West Ham United,” said the manager. “He’s a terrific young talent, who has already shone at the very highest level for Ajax in the Champions League and made well over 150 senior appearances at the age of 23 – so it was no surprise to see so many top clubs chasing his signature this summer.
“The fact we’ve been able to attract a player of his undoubted quality to London Stadium shows the pull West Ham have now – the Board and Tim deserve huge credit for getting this one over the line.”