Hi Ethan,

Thank you for posting in our forums!

The XamDataGrid uses some of our Editors in their templates.  So you will want to target their FontFamily for the font you want to use and then set the Field's EditorStyle property to use the keyed Style you create.

You can see an example of this in my following code snippet.

<Grid>
    <Grid.Resources>
        <Style x:Key="SpecialFont" TargetType="{x:Type igEditors:XamTextEditor}" BasedOn="{x:Static igThemes:EditorsRoyalDark.XamTextEditor}">
            <Setter Property="FontFamily" Value="Times New Roman" />
        </Style>
    </Grid.Resources>
    <igDP:XamDataGrid Theme="RoyalDark" BindToSampleData="True">
        <igDP:XamDataGrid.FieldLayouts>
            <igDP:FieldLayout>
                <igDP:FieldLayout.Fields>
                    <igDP:TextField Name="name" EditorStyle="{StaticResource SpecialFont}" />
                </igDP:FieldLayout.Fields>
            </igDP:FieldLayout>
        </igDP:XamDataGrid.FieldLayouts>
    </igDP:XamDataGrid>
</Grid>

If you have any further questions or concerns with this, please let me know.