Leather jackets are popular as club jackets for various groups. Many of these groups, such as motorcycle clubs or car clubs, offer patches that can be sewn onto the leather jackets. It's possible to sew patches on a leather jacket without ruining the jacket or the lining as long as you have the right items and the know-how.
Identify exactly where you want the patch on the leather jacket using tailor's chalk. In this example, the patch will be put on the upper back of the jacket.
Using a sewing pick, pick open the seam in the jacket lining at the bottom back. Open it up just enough to allow your hand to fit inside. Position your hand inside so that it is resting flat between the lining and the marked area. Your outside hand should position the patch on the leather. You can lightly spray the back of the patch with leather adhesive if desired; this will affix the patch in place for sewing, but it is not permanent adhesive.
Thread an upholstery needle using a strong light-coloured nylon thread. Use your thimble to push the needle through the leather, moving from inside the jacket to the outside for the first stitch. This way, the knot at the end of the thread will be on the inside. Pull the needle out with your outside hand and send it back down through the patch and the leather.
Stitch the patch on by sending the needle back and forth through the leather and the patch, all the way around the patch's edges. Keep using the thimble to push the needle in without bending it. Keep stitches close to the edge and close to each other for the most secure stitching.
Continue around the patch until you end up where you started. Then, send the needle through the first stitch and loop it around to make a half hitch. Do this a few more times to make a finishing knot. Trim the leftover thread close to the patch so the stitching is smooth.
Restitch the jacket lining after removing your hand.
Remember that where you sew a patch on leather, there will always be holes from the needle, even if you remove the patch someday. Make sure it is exactly where you want it before sewing. If you are hesitant to sew a patch on a leather jacket yourself, check with the nearest leather or shoe shop to see if they will do it.
Don't use cotton thread for sewing patches onto leather. The chemicals used to tan leather will weaken the cotton thread over time.