I know a lot of experts say using a journal for tracking food intake helps with weight loss, but has anyone ever done this for exercise? I'm curious whether tracking progress in my exercise frequency, repetitions, and improved time can aid in my weight loss efforts.

I think journaling your exercise is a good idea.

It can be as simple as what you did and the time or distance for each exercise
or
You can make it more complicated than that.

I use to put a sticker on my daily chart when I did one.
I know that sounds kid like but it was rewarding to me.

I use journaling for exercise off and on. It's esecially helpful when I'm doing something new or shooting for a goal, such as running on the track once each week or going for a longer bike ride.