The service, held to mark the surrender of Japan at the end of World War Two, was led by Reverend Canon Bob White.
The event included readings from Burma veterans and a performance from the Portsmouth Military Wives Choir.
The service saw wreaths laid at the war memorial, including one on behalf of the city placed by the Lord Mayor of Portsmouth, councillor Frank Jonas.
Council leader Donna Jones said: "It's important for communities to commemorate events such as these.
"The ceremonies in the city provide a poignant opportunity to reflect and remember."
A special VJ Day Choral Evensong was due to take place from 18:00 BST at Portsmouth Cathedral on Sunday.

Anna O'Flanagan, Katie Mullan and Zoe Wilson netted the goals for the Irish who had beaten Wales in the semi-finals.
Ireland now turn their focus to World League 3 and the Eurohockey Championships this summer.
"We have had an incredible experience and have grown and learnt a lot as a group," said coach Graham Shaw.
"This is our first competitive tournament in 18 months and we are very proud of the team and the level of performance.
"We will use this tournament as a benchmark going forward. Our number one goal is to qualify for the World Cup and finish as high as possible at the Europeans in August."

Midfielder Garrett scored in the 3-1 victory at Shamrock Park but should not have been on the pitch.
Ards have now been handed the win on a 3-0 scoreline and move up to seventh in the league, with the Ports now eight points adrift at the foot of the table.
The matter was discussed by an Irish FA Disciplinary Committee on Wednesday.
According to the IFA website, Garrett was to serve a one-match ban, effective from Monday 24 October, but Portadown say they understood that the suspension was to commence a week later.
A statement released by the IFA on Thursday morning said the sanction had been imposed for a breach of Article 22.1 of the Disciplinary Code "following consideration of Portadown's written comments".
"The Committee was satisfied that Portadown knew or ought to have known the current rules with regard to suspensions," read the statement.
The issue of Garrett's eligibility was raised by Ards prior to the Premiership game between the sides and formally brought to the attention of the IFA by the Northern Ireland Football League.
The result at Shamrock Park was Portadown's fourth win of season, meaning they would have wiped out the 12-point deduction imposed before the start of the season.
They are now on minus-three points.
Veterans and soldiers attended a ceremony at Portsmouth's cenotaph to mark the 70th anniversary of VJ Day.
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Ireland have won the hockey World League Round Two in Kuala Lumpur by beating Malaysia 3-0 in Sunday's final.
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Portadown have forfeited the points they won by beating Ards on Saturday and been fined £350 for playing Robert Garrett while he was suspended.