British producer Ronson got his first number one with Uptown Funk on 14 December, and the single has now claimed the final top spot of 2014.
It was released five weeks early after it was performed by Fleur East on The X Factor, later topping the iTunes chart.
Haenow had topped the Christmas chart with OneRepublic's Something I Need.
Uptown Funk had dropped one place to make way for the former van driver's track over Christmas.
Fellow Briton Ed Sheeran, who scores a 12th week at the top of the album charts, held on to number three in the singles chart, with Thinking Out Loud.
American singer Taylor Swift moved up three places to fourth with Blank Space, while former X Factor star Olly Murs dropped one to fifth with Up, his collaboration with Demi Lovato.
The only new entry went to Alesso featuring Tove Lo with Heroes (We Could Be).
Sheeran's album logged sales of 211,000, his second biggest one-week sales tally since the LP's release back in June.
The top five was completed by Sam Smith, Murs, George Ezra and Take That, who all held their positions.

The victim, a 33-year-old man, was left in a serious condition in hospital after a "violent attack" on Friday, police said.
A 29-year-old man has now been arrested in connection with the incident and is due to appear at Paisley Sheriff Court later.
The incident took place after the victim left a friend's flat in Argyle Street at about 18:30 on Friday.
He returned to the flat around 01:20 on Saturday, having suffered serious injuries.
The man was rushed to the town's Royal Alexandra Hospital for treatment and police appealed for information.

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After much deliberation, McIlroy last month opted out of the Games, saying he was concerned about the Zika virus.
Speaking ahead of this week's Open, McIlroy said he was "very comfortable" with his decision to pull out of the Olympics, adding he may not bother watching the Rio golf action on TV.
"I'm very happy with the decision I've made, I have no regrets," said McIlroy.
"I'll probably watch the Olympics, but I'm not sure golf will be one of the events I'll watch."
Asked which events he'd watch, McIlroy replied: "Probably the events that…track and field, swimming, diving, the stuff that matters."
McIlroy rejected suggestions that the decision of several top players to withdraw from the Olympics was "letting the game down".
The sport is making its return to Olympic competition after an 112-year absence.
"I don't feel like I've let the game down at all. I didn't get into golf to try to grow the game, I tried to get into golf to win championships," he told a pre-Open Championship news conference at Royal Troon.
"All of a sudden you get to this point and there is a responsibility on you to grow  the game, and I get that.
"But at the same time that's not the reason that I got into golf. I got into golf to win. I didn't get into golf to get other people into the game."
Also in his news conference, McIlroy said that golf had to improve is drug testing policy because it is "some way behind the other sports".
The World Anti Doping Agency's (Wada) most recent report from 2014, revealed 507 tests were carried out on golfers with eight testing positive.
"On average, we get tested four or five times a year. It's very little compared to other Olympic sports," said McIlroy.
Northern Ireland's world number four added: "I have been tested once for drugs this year, the day before the US Open. It was only a urine test, not a blood one.
"But I don't think there are drugs that can make you better across the board.
"There are drugs that can make you stronger and make you concentrate more but not that can make you a better all-round golfer, as far as I am aware.
"I could take HGH (Human Growth Hormone) and get away with it."
Mark Ronson's collaboration with Bruno Mars has reclaimed the number one spot in the singles chart, pushing X Factor winner Ben Haenow down to number two.
[NEXT_CONCEPT]
A man has been arrested over an attempted murder in Paisley.
[NEXT_CONCEPT]
Rory McIlroy has suggested that golf will not be one of the sports that "matter" at next month's Rio Olympics.