Film:
* The Shadow of the Wind (2007): Gratama played the role of "The Shadow" in this Spanish-language mystery film.
* Black Book (2006): He played the role of "Sassen" in this Dutch-language war film.
* The Last Days of Emma Blank (2009): He played the role of "Raymond" in this Dutch-language drama film.
* The Dinner Game (2018): He played "Philippe" in this French-language comedy film.
Television:
* Flikken Maastricht (2005 - 2014): Gratama played the role of "Victor de Bruijn" in this popular Dutch police procedural series.
* The Last Kingdom (2015 - present): He played the role of "Father Benedict" in this historical drama series, a recurring role he has had for multiple seasons.
* Van God Los (2008 - 2010): Gratama played the role of "Jan Vos" in this Dutch crime drama series.
* De Coöperatie (2011): He played the role of "Joris" in this Dutch drama series.
Other Notable Projects:
* The Little Prince (2015): Gratama voiced the role of the "Fox" in this animated film.
* The Wind Rises (2013): He voiced the role of "Kiro" in this Japanese animated film.
This list is not exhaustive, but it showcases some of Gratama's most significant contributions to the entertainment industry. He has a diverse filmography, encompassing various genres and languages.