A brand new Carhartt jacket doesn't have that rugged appeal of a vintage version, but it can be distressed to make it look older and more worn. A Carhartt jacket is made from thick material such as cotton twill, that takes some time to be worn in on its own, so don't be afraid to take the matter into your own hands. Using simple tools and distressing techniques can change the appearance of your jacket within a short period of time.
Wash the jacket multiple times to help break down the fibers of the fabric. Allow it to dry in the sun, if possible to fade the color of the material. For an even more worn appearance, leave the jacket outside in the elements for a few days.
Sandpaper areas of the Carhartt jacket that you want to appear more worn. Good places include the collar, the elbows and the cuffs. Use a gentle touch to determine how much you want the fabric to be distressed. More is less, you can always go back and sandpaper more if the effect is not as great as you want, but you cannot remove the distressed look once it has been applied.
Splatter some paint on the jacket to give it a lived-in and worked-in look. Allow the paint to dry before sanding some of it off with the sandpaper.
Hammer the jacket with a hammer to give it a used appearance. Do not use too much force, as you don't want the jacket material to rip or shred. Start with light hits, progressing to harder ones if you are not getting the look you desire.
Wire brush the collar and sleeves. This will create small frays in the fabric that will make it appear to be vintage.