LocalBitcoins' own announcement of a change of chief executive, published in November 2019, records the founding: "LocalBitcoins.com was created as an easy way for anyone to have access to Bitcoin in 2012 by Jeremias Kangas, who was convinced of Bitcoin's importance in a global economy." The same post says that together with his brother Nikolaus he "saw the peer-to-peer marketplace grow to over 100 000 active users already within its first years of operation", and that when Sebastian Sonntag started as chief executive on 2 September 2019 both brothers moved onto the company board.
The site he built was an advertisement board with an escrow attached, not an order book. Two people agreed a price and a payment method between themselves, the coins sat in escrow until the seller released them, and no bank had to be willing to serve either side. That design is why LocalBitcoins was used heavily in countries where an exchange account was hard to open.
LocalBitcoins Oy closed the trading service in February 2023.