The American beat Russian Aslan Karatsev (30) 7-5, 6-1 in Tokyo to lift his first trophy, just over a year since turning professional.
Shelton's powerful shots and on-court theatrics have made headlines but he said he had made a conscious effort to be "calm, cool and collected" this week.
The world number 19 said his new approach had "really helped me to keep my head on straight".
"How much energy I spend, when to show emotion, when not to show emotion, it's something that I'm kind of learning and figuring out for myself," he said.
"Compared to most of my weeks out on tour, I was much quieter, more subdued this week.
"I think it's all about finding the balance."
Shelton was more composed than world number 50 Karatsev, who smashed his racquet in the second set as the match spiralled out of his control.
Shelton won the first set after breaking his opponent for a 6-5 lead, and comfortably took the second as Karatsev fell to pieces.
Shelton reached the Australian Open quarter-finals in January and the US Open semi-finals last month, and he said that his fledgling career had exceeded his expectations.
"In no way did I expect that my first season on tour would go like this but I'm just taking it and running with it," he said.
"I've really enjoyed all the experience that I've had on tour so far, the wins, the losses - I feel like I've learned a lot about myself this year."
'All business'
Shelton went straight over to hug his father and coach Bryan after Karatsev had hit a shot long to end the match.
Shelton has become known for celebrating wins with his now-trademark "dialled-in" gesture with an imaginary telephone.
He did not perform the routine all week in Tokyo and said he liked to "be creative" with his celebrations.
"One of my friends here was saying if I win I should do this celebration where you act like you're fixing your tie and your suit and holding a briefcase, like it's all business," he said.
"I kind of did that a little bit after I shook hands with the ref - maybe that celebration makes another appearance later in my career, who knows."
Shelton had to work hard to reach the final in Tokyo, with three of his matches going to three sets.
He looked dead and buried in the semi-final, with American Marcos Giron (30) a set up and serving for the match at 5-2.
Shelton said he had found a new resilience and was happy to find stability after "a roller coaster week".
He said he would try to let the title "sink in" before he returns to action in Vienna next week.
"I'm really happy with the way I competed this week and I'm not sure what the future holds," he said.
"I'm just looking forward to tomorrow, looking forward to my next tournament."
