Native River, the 2018 Cheltenham Gold Cup winner, has been retired after failing to finish in the Coral Welsh Grand National on Monday.
The 11-year-old also won the Hennessy Gold Cup and Welsh National in 2016.
In all, he won 11 of his 24 chase starts for trainer Colin Tizzard, bringing in more than £1m in prize money for owners Garth and Anne Broom.
Assistant trainer Joe Tizzard said Native River had been “an absolute legend for us all”.
“His wins in the Cheltenham Gold Cup, the Hennessy and the Coral Welsh Grand National were all massive, memorable days for Garth and Anne and the whole team,” he added.
“He’s a lovely character, and has been a special horse to train. He will now enjoy a happy and well-deserved retirement.”
Having won the Hennessy Gold Cup at Newbury in 2016, Native River added victory in the Welsh National the same season before finishing third in the 2017 Cheltenham Gold Cup.
The following year, he beat Might Bite by four-and-a-half-lengths to win at Cheltenham.
Owner Garth Broom described him as “a horse of a lifetime” adding that “the writing was on the wall” after pulling up in the Welsh National on Monday.
Broom added: “He has been such a grand servant and we decided enough is enough. It is the first time in about 25 races that he has been out of the first four, I think. We have been very lucky to have him.”