The selection is in recognition of the various cities' commitments to placing culture and creativity at the heart of their development and to sharing knowledge and good practices.
Whanganui & Partners embarked on the application process for the City of Design recognition in August last year.
It said creativity, innovative spirit, cultural integrity and strength of artistic tradition helped Whanganui get over the line for the international recognition.
Whanganui & Partners strategic lead of creative industries, Dr Emma Bugden, led the application and worked with more than 100 partners and professional bodies during the process.
Bugden said Whanganui's status as a member of the UCCN would be championed and celebrated and should be a source of pride for the whole community.
"The designation will be at the forefront of Whanganui's profile in the city's promotion and in our sense of identity," she said.
"It is our intention that our city's narrative, the way we speak and think about ourselves, will include our status as a UNESCO City of Design as a matter of custom."
Bugden had contacted all 41 international Cities of Design to notify them of Whanganui's application and had spoken to representatives from Singapore and Geelong, Australia, to gain insight into the process.
The UNESCO Creative Cities Network was created in 2004 to promote co-operation among cities that have identified creativity as a strategic factor for sustainable urban development.
There are 246 cities in the network, all of which put creativity at the heart of their development plans and co-operate with other international cities that share these goals.
As a City of Design, Bugden said Whanganui would learn from and partner with a global network of leaders.
She said being part of the UCCN would strengthen Whanganui's connections with indigenous creatives around the world.
"Particularly focusing on how indigenous voices are reflected in place-making and the visual identity of cities."
Mayor Hamish McDouall said UCCN's aims aligned with Whanganui District Council's philosophy by encouraging partnerships, promoting connectivity and innovative approaches as well as safeguarding cultural heritage and natural resources.
"Our creative environment has always nurtured makers in our community, from our significant artistic legacy to our position as a creative hub.
"Joining other UNESCO Creative Cities will give us a connection to like-minded places and enable Whanganui to contribute our singular vision to this creative community."
Whanganui designer Cecelia Kumeroa contributed to the application and helped host UNESCO commissioners when they visited Whanganui.
"He tohu o te wa," she said. "Our designs are being informed by our awa, our taiao, our histories.
"I am so happy for us all in Whanganui. This is a huge win for us all."
She said her Tupoho group was immersed in design work at the moment.
"We are translating our thinking into an overall narrative for the Tā Archie Taiaroa Pataka - the new wing of the Sarjeant Gallery, where we will embed our cultural symbols and aspirations for the future."
Bugden said Whanganui could celebrate the meaning behind the UNESCO recognition in stories exploring our design heritage.
"Our connection with the network will form a sense of community and supportive understanding as we learn from other cities," she said.
"Reflecting on their stories will allow us to embrace this exceptional status as being a reflection of shared values and character."
Bugden said being a City of Design reflected Whanganui's historical contribution to creativity, from Māori designers' artistry and innovation alongside the awa for more than 800 years, to the visionary architects who created the city's breathtaking landmark buildings.
It also showed the promise of Whanganui's design future.
"Our creatives can take pride in this recognition," Bugden said. "We are confident in Whanganui's ability to contribute to a creative international community."
Bugden was helped by a City of Design coordination team, which included Whanganui District Council heritage advisor Scott Flutey, Whanganui & Partners acting chief executive Jonathan Sykes and senior communications advisor Rebecca Black.