put one's neck on the line

to put one's neck on the line ( to take a risk for someone, to be at risk for someone) — подвергать себя риску; рисковать из-за кого-л.; рисковать ради кого-л.

Example 1: I really put my neck on the line for you to get that job. If you don't do well at it, I could really get in trouble.

see also
[stick one's neck out]
[put one's head on the block]
to take great risks for sb/sth
to go to a lot of trouble or difficulty for sb/sth
cf.
[lay sth on the line]