Mr Maskey took 70.6% of the vote in Thursday's by-election with 16,211 votes. The turnout of 37.53% was one of the lowest for Northern Ireland.
In second place was the SDLP's Alex Attwood on 3,088, with Gerry Carroll of People Before Profit third on 1,751.
The by-election was held after Sinn Fein president Gerry Adams resigned earlier this year to become a member of the Republic of Ireland's parliament.
Brian Kingston of the DUP took 1,393 votes, Bill Manwaring of the UUP 386 and Aaron McIntyre of the Alliance Party 122.
The result was seen by many as a foregone conclusion as it is the safest seat in Northern Ireland, and the fourth safest in the UK.
The full turnout of 37.53% drops to 37.35% when spoiled votes are excluded. The previous record low was 38.75% at North Down in 1995.
Mr Maskey, who is a sitting assembly member and a long-time Belfast city councillor, was also celebrating his 44th birthday.
He said he was not concerned by the turnout, adding that people had been asked to cast three separate votes just five weeks ago for the Northern Ireland Assembly, local government and AV referendum.
He said: "I am delighted to be elected by the people, they have endorsed Sinn Fein yet again for their Westminster seat."
'Strong legacy'
Accompanied by wife Patricia and his brother, fellow Sinn Fein MLA Alex Maskey, he paid tribute to his predecessor as he vowed to improve the lives of people in a constituency that has some of the most deprived neighbourhoods in Northern Ireland.
"This part of the city is moving forward and I will endeavour to be part of that and work tirelessly to do what I can for the people of west Belfast," he said.
"I take on the proud and strong legacy of Sinn Fein party president Gerry Adams and look forward now to the challenges in front of me."
Mr Adams presented his successor with a special hurley to mark the result as other supporters urged him to blow out the candles on a birthday cake.
"It's Paul Maskey's night," said the Sinn Fein president.
"Once again Sinn Fein in west Belfast has delivered and we delivered big time."
Sinn Fein's MPs have not take their seats at Westminster because they refuse to swear an oath of allegiance to the Queen.

Ice Arena Wales will hold 3,088 for Devils home games, a big increase up from the 2,300 capacity at their current Cardiff Bay Ice Arena base.
The Big Blue Tent has been a temporary home since 2006 following the demolition of the Wales National Ice Rink.
"The facility is stunning," Devils managing director Todd Kelman said.
"We are very pleased with it and I know our fans are going to love it.
"There are a few things that still need to be completed, but it is nearly there."
Devils are currently top of the Elite League and host Blaze in the league and Belfast Giants in the Challenge Cup in back-to-back home games this weekend.
Sinn Fein's Paul Maskey has been elected as the new MP for West Belfast.
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Cardiff Devils will play the first game at their new home against Coventry Blaze on 27 February.