Inked-up gunman Daniel King has been farewelled at a funeral almost two weeks after he went on a shooting rampage in Sydney's west, which ended with him being shot dead by police.

More than 200 friends and family sat through the hour-long service at Pine Grove Memorial Park in Minchinbury on Wednesday morning.

The 32-year-old died in a hail of bullets outside Penrith Police Station on October 2 after shooting up the house of his pregnant ex-partner Stacey Taylor, who claimed he wanted her to have an abortion, before turning his gun on police.

Childhood friend Izzy alluded to King's mental health and told mourners that it was not possible for his friends to "fight his battles for him".

"Daniel gave us a lot, but it was sometimes hard for him to receive in return," he said.

"I realise it was not possible for any of us to fight his battles for him.

"Don't blame yourselves or each other but think about what Daniel has taught you.

"I hope that he's resting (in peace) and know that he's loved - I love you brother."

King was raised by his parents Sandra and Peter in Lidcombe before moving to Cambridge Gardens and Doonside.

He attended Patrician Brothers Blacktown and, while still at high school, became a father to his son.

He converted his parent's garage into "Kingy's gym" to work out and dreamt of playing first grade rugby league.

But mourners were told King's dream came crashing down at 23 when an on-field accident caused a delayed stroke, leading to brain injuries.

King later went on to work in the juvenile justice system and fathered a daughter.

During the service, circumstances surrounding King's death were not mentioned but several speakers repeatedly mentioned his drawn-out struggles with mental health following his stroke.

Long-term friend Keith Peters said King's greatest achievements were his kids.

"For all Kingy's achievements and attributes. I know his greatest joy was his kids," he said.

"We were still in school when (his son) was born … he just wanted the best for his son.

"Recently, (his daughter) came into his life and changed his perspective.

"So in the future if Daniel's kids … want to know how much he loved them or who he was as a person, I can only tell them what he was to me - he was unbelievably strong-willed, determined, extremely caring and always stood up for the underdog.

"He loved his kids above all else and he was my loyal friend."

Another friend Arnold addressed King's two children and said he wasn't "perfect".

"May you both be reminded that Daniel was not perfect but he loved you dearly.

"In these moments it's best to remember the best - Daniel did struggle to over-strive for positive outcomes."