Kral arrived in London on a season-long loan on the last day of the transfer window from Russian side Spartak Moscow.
He joins fellow Czech Republic internationals Soucek and Coufal at the London Stadium, two players who have been integral parts of the West Ham squad ever since their arrival.
Moyes praised the youngster for being an exciting prospect and stated that he will provide some valuable depth to his side with the Hammers’ busy schedule this season.
The West Ham boss added that he is hopeful that Kral will follow the example of Soucek and Coufal in showing the same commitment to the team as the duo and become an important part of the squad.
Speaking to West Ham’s official site, Moyes said: “He will provide good competition in the centre of midfield.
“He is another young, talented player who we feel has a big potential and will be capable of adapting to the demands of the Premier League.
“We’ve brought him in on loan initially and, hopefully, over the course of the season he will make a valuable contribution, particularly with our busier schedule of fixtures.
“Alex is another established international player with the Czech Republic, and we hope he has similar characteristics and hunger to that of Tomas [Soucek] and Vladimir [Coufal].”
Coufal and Soucek both played vital parts in helping West Ham secure European football last season and with the addition of Kral, as well as Nikola Vlasic on deadline day, Moyes will be hoping his side reach even greater heights this campaign.