The rebrand follows the purchase of the business in September by 33-year-old managing director Gwyn Jones from the founders Simon and Ruth Macbryde.
Gwyn Jones has financial backing from Bridgemere, which is owned by Redrow founder and former chairman Steve Morgan.
Macbryde Homes built 182 homes in the year to 31st March 2019 and turned over £30m. Castle Green will complete more than 200 homes this year and is aiming to quadruple in size over the next five years.
Mr Jones said: “We’re all excited at the prospect of rapidly increasing the number of new homes we build and becoming a major force in the region. Alongside this growth we are fully committed to offering a market leading customer journey and being the homebuilder of choice for new home buyers.”