He returned to Auckland in 1952 and shifted his artistic focus to Maori designs in Tā moko (facial tattooing), carved gourds,[4] and kowhaiwhai (rafters of meeting houses).

In 1963 his gourds were the only artwork by a Pakeha (non-Maori) featured in an exhibition of Maori art held at Turangawaewae marae, Ngāruawāhia.

Martin Rumsby was with Schoon during some of his explorations in the Waiotapu geothermal area when it was not as well known, writing: "Theo told me that nature worked in repeating cycles – that was his theory.

He moved to the West Coast of New Zealand – the source of the stone – and was employed by the Westland Greenstone Company in Hokitika in 1970.

He did some major research into jade carving at this time including a trip to Hong Kong but was dismissed from his employment in 1971.

Throughout his life he took numerous jobs to make ends meet while he pursued his art including working as a nurse at Auckland Mental Hospital in Avondale in 1949 and as a farm worker at the Mt Albert Plant Research Station in 1952.

His extensive archive including sketch books, photographic negatives and correspondence was purchased by the Museum of New Zealand Te Papa Tongarewa.

Schoon's work was multidisciplinary, often focusing on abstract forms, surreal landscape photography and minuscule worlds.