The character was introduced alongside his twin brother Leo Tanaka (Tim Kano), and they arrive in Erinsborough to find their long-lost biological father.

Having been pressured by his great-grandmother Kazuko Sano (Linda Chin) to settle down with a woman, David finds it difficult to deal with his attraction to the openly gay character Aaron Brennan (Matt Wilson).

Honda chose to leave the role in 2021, though the cancellation and subsequent revival of Neighbours saw David remain in the series until his death on 1 February 2024, followed by voice cameos on 28 March and 1 April of the same year.

[6] When David and Leo spend more time in Erinsborough they befriend Aaron Brennan (Matt Wilson), Amy Williams (Zoe Cramond) and Elly Conway (Jodi Anasta), setting the characters up to become intertwined in one another's storylines.

[21] The storyline reached a turning point as David decides to confide his fears about being gay to the local priest, Father Jack Callahan (Andrew James Morley).

Neighbours' executive producer Jason Herbison was delighted with the change, though he believed that the characters should be like all soap couples and face challenges before marrying.

"[38] Neighbours script producer Shane Isheev used his own experiences and relationships to inform David and Aaron's story, and wished for the couple to be "the next Karl and Susan".

"[35] In April 2020, it was announced that David and Aaron would explore adoption and foster care in a new storyline, which saw Ezra Justin join Neighbours as teenage boy Emmett Donaldson.

[46] This followed the earlier announcement that Deborra-Lee Furness, who previously appeared in Neighbours as Linda Hartley, would direct episodes that saw a couple become permanent carers to a displaced child.

[47] Furness stated that she was "thrilled to be collaborating with the team at Neighbours to direct these episodes and tell a story that is not often represented in mainstream media", hoping that the awareness raised would encourage "a positive shift in both culture and policy towards permanent solutions" to Australian out-of-home care.

Blythe stated that "the Neighbours team were very receptive to my feedback, and worked to ensure that the experiences and behaviours of Emmett, David and Aaron provided an accurate representation of out of home care in Australia".

"[48] Honda stated that "a lot of foster kids who have experienced trauma react in very strong ways, the fight or flight response can be incredibly strong… because they feel threatened.

The getaway also provided a turning point for the recently introduced character Freya Wozniak (Phoebe Roberts), who had been searching for her partner, Gareth Bateman (Jack Pearson) after he went on the run from a criminal gang.

Gareth surfaced at River Bend, revealing that he was in league with the gang and attempting to kill Freya and Levi Canning (Richie Morris) to cover his tracks.

[56] Honda expressed his pleasure over the entirety of David's arc on screen, highlighting the "strength" he found through coming out and the challenge to his morality over the previous year.

[69] Honda reflected that David "started off as this reserved, closeted man who didn't have all this confidence in the world outside of when he was working - now, he's in a place where he's being a hero and saving his brother's life.

[69] Honda stated that "the way that the show has built this story, and also executed it at such a high level, means that it hopefully will go down as one of the major deaths in Neighbours history for good reasons and not bad ones".

[69] Honda further stated that he was allowed input into the realisation of the storyline, particularly through the voice memo that David records for Aaron before he dies, which was agreed upon but not initially included in the episode's script.

The voice memo allowed David to urge Aaron to move on, though Honda mused that the nature of Neighbours may cause this to happen sooner than his character would like.

[71] While visiting his great-grandmother at Erinsborough Hospital, David befriends Paige Smith (Olympia Valance), who tells him about Angelina Jackson (Sarah Howett), a patient who has a brain tumour.

When Xanthe Canning (Lilly Van der Meer) is accused of taking the painkillers, David confesses his guilt to Clive Gibbons (Geoff Paine).

David and Aaron become foster parents to teenager Emmett Donaldson (Ezra Justin), despite initially requesting a younger child, and soon form a close bond with him.

Although Nicolette successfully conceives, matters are complicated when she begins a relationship with Aaron's sister Chloe Brennan (April Rose Pengilly), and Emmett and Brent return for a time.

When Nicolette suddenly leaves Erinsborough close to her due date, David is distraught and risks his career by attempting to find information on her whereabouts through medical records.

Their deceptions are exposed when Abigail's mother, Britney Barnes (Montana Cox), briefly kidnaps her baby, prompting Nicolette to return and reveal the truth about the two infants.

Fearful of Nicolette running away again, David and Aaron use Paul's help to hire lawyers in an attempt to gain full custody, but eventually agree to a shared parenting arrangement.

When David then encounters a critically injured Gareth Bateman (Jack Pearson), who has been thrown out of a bus windscreen, Freya Wozniak (Phoebe Roberts) informs him that he is Aaron's attacker as he prepares to treat his injuries.

Two years later, David, Aaron, Nicolette and Isla have moved to the country, where they run a guest house, after Paul involved them in the cover-up over Krista Sinclair's (Majella Davis) apparent death and jilted Terese at their vow renewal.

David has disowned Paul over his behaviour, but returns to Erinsborough with his family upon learning that Melanie Pearson (Lucinda Cowden) is revealing the truth to Terese and Toadie Rebecchi (Ryan Moloney), who she is now married to.

Later, Aaron finds a voice memo on David's phone, where he insists that he had to save Eden's life, gives Paul his forgiveness and says goodbye to his family.