Elder said he was aware the march would pass a Riccarton Rd motel where he was staying while his earthquake damaged home is repaired and decided to track it to a rally point at a nearby park.
"I'd thought about this a couple of days in advance and I'm interested in seeing what goes on at these."
During his time as Solid's chief executive he'd warned people rather than "go home and have a glass of chardonnay" they should meet protests head-on.
"You need to make a decision that you want to stand up and be counted at these things and say what you think - I said I better apply this to myself [and] followed them to where they were gathering just down the road."
Along the way he was invited five times to sign a petition opposing the process but declined the offers.
At the gathering he offered to speak for two minutes on how the part sale of Solid could benefit the country but was disappointed to be knocked back.
"It's not often you get the CEO of a state-owned enterprise showing up at an event like this."
He said he would have told the crowd at the meeting last weekend that Solid Energy had grown rapidly but needed access to more capital to grow.
"The current Government is not in a position to give us more capital."
Elder said Solid's strategy of the past seven or eight years meant the company was now capital constrained.
