Its cabinet backed the signing of a new host agreement which will see the annual triathlon stay in Pembrokeshire until 2021.
A report said the event, which had almost 2,000 competitors last year, is worth £3.7m a year to the economy.
It attracts athletes and visitors from around the world and "places Pembrokeshire on the global scene".
The agreement is currently being finalised and it will see the event - which comprises of a 2.4-mile (3.86 km) swim, a 112-mile (180.25 km) bike ride and a marathon - rebranded as Ironman Wales Pembrokeshire.
The report said Pembrokeshire Coast National Park Authority has agreed to support the council's contribution with £16,000 a year, while Tenby council has committed £5,000 for the first year.
Narberth, Pembroke and Saundersfoot councils were approached but declined to contribute.
The Ironman Wales event was first hosted in Pembrokeshire in 2011 and Pembrokeshire council's cabinet approved the recommendation on Monday.
Pembrokeshire council will pay £50,000 to host Ironman Wales after agreeing to back a new deal.