[2] McMahon was involved in Johann Lamont's successful campaign in the 2011 Scottish Labour Party leadership election.

Following Lamont's victory, McMahon became her Parliamentary Private Secretary (PPS), with the right to attend meetings of the Scottish Labour Shadow Cabinet.

[4] Following Johann Lamont's resignation as leader following the 2014 Scottish independence referendum, McMahon supported Jim Murphy in the 2014 Scottish Labour Party leadership election, and afterwards he gave her a junior role as Shadow Minister for Youth and Women’s Employment, reporting to Shadow Cabinet Secretary for Fair Work, Skills and Training Neil Findlay.

[5] McMahon endorsed Richard Baker, then subsequently Ken Macintosh in the 2015 Scottish Labour Party leadership election.

In response, Dugdale invited all non-returning, including regional list, MSPs to a dinner she would be hosting the following week.