People mounted school buses in Times Square, sweated as they flowed en masse down Eighth Avenue, and screamed and lit fireworks in the streets.

Dogs wore orange and blue, and children stayed up long past their bedtimes.

The Knicks had won their first N.B.A. championship in more than 50 years, and the city welcomed it in true New York fashion: extravagantly.

Cars honked as traffic on Fifth Avenue was gridlocked with marching fans.

“Let’s go Knicks!” they roared.

Thousands packed into a watch party at Plaza33 outside Madison Square Garden, shouting and crying as the final seconds of the decisive Game 5 against the San Antonio Spurs ticked away. Steven Silfa of the Bronx lingered for the trophy ceremony on the big screen, just to stay in the moment.

“The Knicks — my whole life, I’ve never seen anything like this,” Mr. Silfa, 37, said as Frank Sinatra’s voiced boomed over the loudspeakers.

The city has been turned upside down.

In Prospect Heights, Brooklyn, Joey Dehnert and his wife, Jill Dehnert, woke up their 5-year-old son, Albie, as they struggled to contain their excitement after the Knicks won.

The young family left their apartment and joined the legion of fans in orange and blue singing and dancing at a pop-up block party. Mr. Dehnert propped Albie on his shoulders.

Asked how he felt after he being awakened from a deep slumber — something the Knicks’ long-suffering fans can relate to — Albie said, “Very happy.”

Bernard Mokam and Sean Piccoli contributed reporting.