Traf took the lead in the 25th minute of a hard-fought contest at Flixton, Luke Jones firing in from the edge of the box.
Angel were soon level though, Chris Nelson's long throw-in finding Cameron Dobson to slam home the equaliser.
The hosts took the lead for the first time in the contest through a stunning strike from Jamie Bradshaw, who ran onto a ball over the top and smashed a first-time strike into the top corner.
It was soon 3-1 to Dan Jones' side, Curtis Rose bringing down James Gunn in the box and allowing Martin Cooper to slam the resulting penalty straight down the middle and into the net.
Any hopes of a Trafalgar comeback were then dashed as they were reduced to nine men, first Wayne Aziz being sent off after a late challenge before Sean Exley followed, given his marching orders by referee Kev Crick for dissent.
Angel took full advantage of their numerical advantage, Cooper lobbing in their fourth before Bradshaw also grabbed his second and his side's fifth and final goal with a composed finish.
Delighted Angel player-boss Jones said: "I'm delighted, we said at the start of the season we wanted to win the league and now we've shown we are capable of doing it.
"We were the better side and were in control before they had two players sent off.
"I can't single out a man of the match, the whole side were brilliant, but I'd like to mention keeper Joe Wright, who made a few good saves in the first half."
Traf boss Col Jenkinson was left fuming by both the performance of his side and the referee.
"The referee was a huge spoiler, but it was a poor performance all-round.
"We should've had a penalty at 1-1 when Sam Pickard was brought down."
West Pier won 6-2 at Roscoes Bar in the other game in Division One.
Roscoes were made to pay for missed chances, spurning several one-on-ones and also hitting the post twice.
They took the lead through man of the match Raul Aldea, but Pier raced into a 3-1 lead.
Matty Rowley hit back for Bar, but Pier wrapped up the points with three further goals.
Ayton's game against Fylingdales was called off due to a waterlogged pitch.
The major talking point in Division Two came at the game between Fylingdales Reserves and Valley, the hosts refusing to come out for the second half, resulting in the game being called to a premature halt.
Valley went into the break 2-1 up courtesy of goals from Paul Nuttall and Sam Westmoreland, a Sam Russell penalty reducing Dales' deficit just before the break.
Unfortunately for the hosts, Dylan Goldsmith suffered a serious knee injury and couldn't continue, with a couple of Fylingdales players claiming they were injured and refusing to go out for the second half.
A decision on whether the result will stand and what sanctions Fylingdales will face will be discussed at the next league committee meeting.
Ayton Reserves enjoyed a comfortable morning as they romped to a 22-0 win at Golden Last.
Si Coupland and Luke Chambers both banged in five goals apiece, Chambers also setting up three goals.
Chris Hannam bagged a hat-trick and four assists, netting him the man of the match award, while sub Dave Phillips scored twice.
Ayton's other goals came from Ste Molloy, Leroy Donaldson, Nicko Dunn, Liam Scott, Scott Davison and two own goals.
Radio Scarborough v Hush was called off due to a waterlogged pitch.