Olympic champion Brownlee, 26, duelled with younger brother Jonathan for much of the race but pulled away when he upped the pace over the last five kilometres to take the gold.
He crossed the finish line in one hour 48 minutes 50 seconds at the Strathclyde Country Park, 11 seconds ahead of his sibling.
South Africa's Richard Murray finished strongly to take bronze.
Commonwealth Games
Thompson-Herah wins 200m gold at Commonwealth Games
06/08/2022 AT 22:00
Earlier, England's Jodie Stimpson claimed the first gold medal at the Games with victory in the women's triathlon.
With Stimpson's compatriot Vicky Holland finishing third, England took four medals from the Games' first two medal events.
Commonwealth Games
Semenya, Cheptegei double up as class shows on Gold Coast
13/04/2018 AT 14:40
Commonwealth Games
Brownlee brothers rue 'terrible' day after failing to medal in triathlon
05/04/2018 AT 07:13