Underline Chart Title

Not that I am aware of. You would need to create a line graphic and do some strategic placement.

hi, rosscortb

After my test, I'm afraid it couldn't achieve in Power BI for now.

You could only format font color, background color, Alignment, Text size, font family for Chart Title for now.

and you may try this special method for your requirement:

After you format title is done, the drag a line from Home->Insert->Shapes->Line

then adjust the line color and size then rotate to horizontal.

finally, move it under the chart title.

For example:

It has the underline for chart title

Best Regards,

Lin