The 35-year-old former world number two beat ex-world champion Shaun Murphy 7-6 in the final of the non-ranking tournament.
Carter, who has overcome testicular cancer, was diagnosed with lung cancer in May.
Carter, nicknamed 'the Captain', wrote on Twitter: "Today's the day the captain became the general."
He added: "Can't believe I am the General Cup champion. Beating a great player like Shaun Murphy."
A gracious Murphy said: "Feel very honoured to have witnessed Ali Carter's return to snooker. Congratulations on a great week back mate and here's to many more."
Seven-time world champion Stephen Hendry said: "I am not surprised by Ali Carter's win, he is a great snooker player!"
World Snooker chairman Barry Hearn said: "Congratulations! You should be very proud of yourself."
Twice beaten in the World Championship final by Ronnie O'Sullivan, in 2008 and 2012, Carter's most recent ranking title was the 2013 German Masters.
He was set to make his competitive return from cancer in Bulgaria in September, but was advised to rest after pain in his left arm prevented him from practising.
The General Cup is not a ranking event, with next one the International Championship in China starting on 26 October, while the prestigious UK Championship in York begins on 25 November.
Ali Carter won the General Cup title in Hong Kong, his first event since starting treatment for lung cancer.