Chengdu lost their last four matches to give up a lead which once stood at 12 points, allowing Dalian Yingbo to overhaul them and claim a first CSL title after a 3-1 win over Tianjin Tiger on Sunday.
"Mr. John Aloisi will no longer serve as head coach of Chengdu Rongcheng Football Club, and his staff will leave together," the club said in a statement on its official WeChat account late on Monday.
The former Australia international striker, who took over for this season, was not the only head to roll with the club also announcing that Chairman Wang Lei and General Manager Wu Bo had resigned.
Chengdu Rongcheng were in the Chinese fourth division as recently as 2018 before making their way up the pyramid to reach the top flight in 2022.
They finished fifth, fourth and third twice in their first four seasons and needed only a single point from their last four games to secure a first title this year.
Sunday's 3-2 loss to Shandong Taishan handed Dalian the title on a better head-to-head record after they recorded a pair of wins over Chengdu, including a 1-0 victory in the penultimate round of matches.