After McKennie's early opener, Wednesday's game was stopped for one-and-a-half hours due to lightning, but USA were not to be denied when the clash resumed in the 16th minute, with Pulisic doubling the lead seven minutes into the second half.
The US did concede their first goal of the tournament as Jamaica substitute Shamar Nicholson set up a nervy finale with 21 minutes remaining but Pulisic capitalised on another rebound to make sure of the result in the 87th minute.
It was a rematch of the 2017 final won by a Bruce Arena-led USA and the hosts burst out of the blocks and were relentless in attack, with Jamaica goalkeeper Andre Blake preventing a certain goal by somehow denying Paul Arriola from point-blank range in the fourth minute.
But USA were not to be denied five minutes later as Bradley picked out Reggie Cannon before Jozy Altidore laid the ball onto the oncoming McKennie, who fired past Blake.
However, USA's momentum was abruptly halted by a lengthy delay due to serve weather in 16th minute and the temporary suspension aided Jamaica.
Jamaica emerged from the delay with renewed energy and looked far more threatening, while the United States were disjoined and lacked rhythm.
The half-time interval provided USA with the chance to regroup and the Americans did just that as they moved 2-0 ahead through Chelsea-bound Pulisic in the 52nd minute.
Morris latched onto a McKennie pass and managed to get a shot off, with Blake only parried the ball straight into the path of Pulisic, who tucked away the rebound.
After Gyasi Zardes wasted a great chance for USA, Jamaica's Nicholson headed a Leon Bailey cross into the net to pull a goal back for the 2015 and 2017 runners-up, only for Pulisic to pounce on another rebound with three minutes remaining.
Another final for USA
After the pain of missing the 2018 World Cup, USA's rebuild under Berhalter continues to gather pace. Mexico stand in the way of back-to-back Gold Cup triumphs in the first final showdown between the nations since 2011.
Bradley, McKennie impress
It was a fine team display by USA. Not short of critics, veteran midfielder Bradley was cool and calm in possession with his passing a clear highlight. Schalke's McKennie, meanwhile, showed why he is so highly rated with a goal and a couple of defence-splitting balls.
Jamaica can hold heads high
For much of the game, Jamaica were outclassed. But the Reggae Boyz, despite limited resources compared to their USA counterparts, made it tough for the six-time champions just like they did in the 2017 final.
USA will look to retain their crown again Mexico in Chicago on Sunday, while Jamaica can look ahead to the CONCACAF Nations League – starting against Antigua and Barbuda on September 6.