The British driver sealed his first title by 12 points from Menu with Yvan Muller a further eight points back in third - clinching the top three places for Chevrolet in their last race as a manufacturer.
After being forced to retire from the first race when he collided with the barrier, Huff took to the grid 17 points ahead of race one winner Muller and with a 19 point lead over Menu meaning he could finish no lower than sixth if either of his team-mates won race two.
Menu, who started in seventh spot on the grid - just ahead of Muller and Huff in eighth and ninth - kicked off strong in the chase of early leader Norbert Michelisz. Alex MacDowall and Pepe Oriola followed closely behind.
It did not take long, and by lap three the Swiss driver had picked his way up the order to take the lead, just before Muller ran straight into the back of MacDowall to send his Chevrolet into the barriers.
MacDowall got out of his car unharmed but the incident brought the safety car out for four laps to clear the damage, which also included Mehdi Bennani's car which had stopped in a separate incident.
The race resumed with three laps to go, but it was not long before the safety cars were deployed again after Michelisz and Oriola clashed, the latter sending the former spinning into the wall.
Huff managed to slip past Oriola and move into second place behind Menu in time for the finish.
Cambridge's Huff said: “I’m pretty speechless. I think it will take quite a while to sink in, if I will ever do. It has been an emotional weekend and an amazing day, especially considering that I have nearly spoiled everything with my incident in the first race.
"What a mistake from me it was! But we had an happy ending. So we will ignore that…
"I had just overtaken Yvan on the inside of the Lisboa, and I was very happy about that. I did not have the time to rejoice, because half-a-lap later I lost the car and crashed.
"I have to say thank you to the RML team, because they all jumped to my car when I pitted. There was quite a lot of damage to be fixed before the second race. They did a great job and for the second race my car was perfect.
"Obviously in between the races I was a bit tense, but still I had a good margin of points and I knew that, even if Yvan or Alain were going to win the races, all I needed to do was to finish no lower than sixth. After the first safety car I was fifth behind Yvan, so it was just a matter of stay focused and not to make any other mistake…
"The team made a gamble on me when they picked me up back in 2005 and I hope that today I have shown they had made the right decision.”