The pair, pictured below at the Cannes Film Festival, married during a romantic sunset ceremony surrounded by family and friends, including Reese Witherspoon.
Also present at the nuptials on Saturday were the couple's two children – Levi, who turns four next month, and daughter Vida, two-and-a-half.
Matthew looked dapper in a a three-piece black Dolce & Gabbana tuxedo, while his 29-year-old bride was beautiful in a wedding gown handmade by one of her favourite Brazilian designers and white Stuart Weitzman heels.
The wedding was a laid-back affair, with guests spending the night in state of art tents – complete with air conditioning, furry white rugs and beds – which were pitched in the back yard of the couple's three-story, seven-bedroom mansion in Austin.
The ceremony was overseen by a local pastor and a monk, and a source told Us Weekly that they kept the words of their vows private.
The insider said: "They whispered them in each other's ears. No one knew what they said. Whatever they said was very emotional. [Camila] was tearing up."
Camilla has officially taken her husband's last name, and will be known as Camila McConaughey from now on.
Matthew, who popped the question on Christmas Day, got together with the sunning Brazilian in 2007.
He had previously dated Penelope Cruz and Ashley Judd before finding lasting happiness with his model love.
For her part, Camila recently said she didn't expect marriage to change their relationship in any way.
"We've been living a married life for over six years now," she says.
"We have homes together, we have family together, we have kids, we've built a life together. So, we've been living a married life this whole time."