From all accounts he was soft spoken and polite - but effective.
To many of those gathered on Monday for his funeral, it was his criticism of Thailand's harsh lèse-majesté law - Article 112 of the criminal code that punishes those deemed to have insulted the King, Queen, heir or regent - that was his downfall.
An unknown gunman killed him on April 23 in a car park, pumping bullets through the window of his car in broad daylight.
Police say three people may have been involved in the well-planned attack, and have not ruled out a personal feud as the motive. But to the hundreds who turned up for Mr Kamol Duangphasuk's cremation on Monday at the Buddhist temple Wat Samien Naree, it was political.
Red shirt leader Weng Tojirakarn called the killing of the man more widely known by his pen name Mainueng Kor Kunthee, an "assassination" meant to be a warning to the red shirts. But he cautioned that the movement must stay calm and not deviate from non-violence - something easier said than done when there are radical groups on both sides of Thailand's volatile political divide.
The People's Democratic Reform Committee (PDRC) has been campaigning since last November against the government of Ms Yingluck Shinawatra, which was swept to power in 2011 partly with the help of the red shirts.
The PDRC which is assumed to have powerful backing, detests Ms Yingluck and her billionaire brother Thaksin Shinawatra, seeing the latter - in self exile dodging a two year jail term for corruption - as a closet Republican who buys votes to win elections.
The subtext to the funeral was never far from the surface. A 64-year-old housewife Sumalee Kongmanee was there, and told The Straits Times: "I never knew Mainueng, but I heard him on the radio. He talked about how some laws are not fair - like Article 112. I haven't studied much, but I know what he said is right."
She was not the only one to have been swayed enough not by actually encountering the poet but by hearing what he said, to come to the funeral.
It was also an occasion for red shirt leaders to show unity even as several have their own favoured strategies and the control of the United Front for Democracy against dictatorship (UDD) umbrella group leaders is sometimes tenuous.
The UDD's former chairwoman, Thida Tawornseth, told The Straits Times: "We can't order all of them. We can just guide them."
Asked what he thought of the strategy of north-eastern red shirt leader Suporn Atthawong or "Rambo Isan" who is organising thousands of "volunteers for the protection of democracy" and having them take rudimentary self defence training, Dr Weng Tojirakarn said he was just "showing off".
"But we don't reject him as long as they are unarmed," he said. "Once he starts arming, we will reject them."
Mainueng was active in the red shirt movement since 2006, when royalist protests in the streets paved the way for the army to intervene and throw then premier Thaksin out of office. In 2010 he apparently fled the country for a while, holing up with other red shirt figures in Cambodia in the wake of the army's crackdown on the movement.
In his talks and his writings, he advocated changes to Article 112, which mandates up to 15 years imprisonment for those found guilty. Under the Article, anyone can file a complaint and it is mandatory for the police to investigate.
Changing Article 112 is seen by many royalists as opening the door to anti-monarchists. The monarchy in Thailand is on paper above politics, but in reality the current King Bhumibol Adulyadej, the longest reigning monarch in the world, is the country's highest moral authority. Political parties jostle to claim greater loyalty to the King. But the King is an increasingly frail 86-year-old and there is much anxiety over the impending transition.
With the current conflict into its sixth month, and related violence having claimed over 20 lives and left hundreds injured in clashes, shootings and bomb attacks, there is some fear that Mainueng's murder could trigger revenge killings.
But the funeral itself will ultimately be a footnote in a larger power struggle over the country's future. Thailand is in the vortex of a major change.
"This is the last war for them, not for us," Ms Thida said.
In an article titled "Courting disaster: Can Thailand's Monarchy survive Democracy?" uploaded on April 22 in the Indo Pacific Review, independent scholar David Streckfuss, author of a book on Thailand's lèse-majesté law, wrote: "No matter how this latest conflict is resolved, the crisis of the monarchy remains."
He warned: "The more the royalists draw on the monarchy to legitimise naked attempts to thwart democracy, to claim exclusive loyalty to the throne, and to use the lèse-majesté law against perceived enemies, the farther the star of the monarchy will fall."
One man at the funeral on Monday, who puffed up his chest proudly and identified himself as a retired officer of the Royal Thai Police, said Mainueng "talked about something in Thailand which you cannot talk about." He gestured to the sky in a common reference to the monarchy.
But he declined to give his name and a formal interview, saying "I can't talk about it until I die."