The hugely talented teenager will be trained in Manchester by four-time world champion Ricky Hatton and is likely to make his debut in the autumn.
Arrowsmith, 19, was highly decorated in the unpaid ranks, winning five national titles and presenting England on numerous occasions.
Now he feels the time is right to turn over and believes Hatton is the man to take him to the top.
“Ricky is one of the best boxers to come out of Britain and just to talk to him and listen to him is amazing,” Reuben, who will box at light-middleweight, said.
“The experience you get from talking boxing with him is something in itself and what he teaches in training is even better. I’m on top of the world.
“Lindon Newbon has brought me on in the last six months and I’m ten times better than I used to be. Now I’m working with Ricky day to day, the only way is up for me. I’ve got a great team around me and if I fail to reach my potential then I’ll only have myself to blame.
“With hard work and a bit of luck, I hope to reach my full potential. I’m 19 now and I think it’s the right time to turn over. I’m ready to push on and make something of myself.”
Ricky Hatton said: “I’ve very excited to be working with Reuben. He’s very talented and although we’ve only been together for a short time, I like what I’ve seen.
“Like anybody who has come from the amateur game, there are things we’ll need to alter style wise but he has that much ability that he’ll take to the pros like a duck to water.
“Every day I’ve worked with him, he’s learned something new and he’s a great listener. I think I can do really good things with him and I’m sure he’s going to win a lot of belts. I think he can go all the way.”