In 1996 Kreiz moved to London to launch children's television network Fox Kids Europe, a joint venture with Rupert Murdoch's News Corporation.

During his tenure, Fox Kids expanded into one of the largest pay-TV channels in Europe and the Middle East, broadcasting in 56 countries in 17 languages.

[3] From 2008 to 2011 Kreiz served as Chairman and CEO of Netherlands-based global television and digital production company Endemol, known for unscripted reality programming hits such as 'Big Brother' and others.

During Kreiz's tenure, Endemol "strengthened its creative output, diversified its lines of business, completed highly accretive M&A transactions, expanded geographically, reduced its cost structure and entered into new strategic relationships.

[2] In addition, changes in consumer media consumption required diversifying risk; Kreiz is credited with restructuring Endemol's creative profile and business operations through expansion from reality television into scripted programming and distribution.

[2][11] In 2012, Kreiz invested in[12] and joined the board of Los Angeles based multi-channel network Maker Studios as Chairman and in 2013 became CEO.

[21] Under Kreiz’s leadership, the company has expanded with more entertainment offerings, products, digital games, publishing, and live events.

[34] Kreiz was also honored as one of Time Magazine’s 100 Most Influential People of 2024 and earned Cannes Lions’ Entertainment Person of the Year Award for 2024.