Ruud floated past Norrie 6-0 6-2 for his fifth title of the period – more than some other player on the ATP Tour.
Ruud, who beat previous world number one Andy Murray in the second round, lost only one set all through the competition.
However, there was British triumph somewhere else in San Diego as Neal Skupski and Joe Salisbury won the men’s copies title.
They beat Australia’s John Peers and Slovakia’s Filip Polasek 7-6 (7-2) 3-6 10-5.
“An incredible week for us,” said Salisbury. “Going into it the objective was to win the competition, yet we didn’t have the foggiest idea what’s in store.”
Ruud overwhelms to better Djokovic on titles count
Norrie, positioned 26th, made a superior beginning to the subsequent set, chopping down his natural blunders before Ruud broke to take a 4-2 lead, proceeding to take his first hard-court title.
Triumph puts Ruud, 22, one in front of Novak Djokovic, Daniil Medvedev, and Alexander Zverev on the leaderboard for most titles this season.
Norrie, 26, has arrived at five finals this season, however, won just one title – his first on the ATP Tour – in Los Cabos in July.
“It’s a pleasant comment, yet clearly Daniil and Novak have greater titles, so I wouldn’t see any problems with changing around with them on the off chance that I had a chance to switch five 250s to three Slams and a 250 Novak has,” said Ruud.
