The MP for Hertsmere rebelled against his party by opposing a ban on smoking in private cars.
The House of Commons on Monday voted in favour of the Labour-supported amendment to the Children and Families Bill by a majority of 269.
The amendment, passed by 376 votes to 107, gives ministers the power to make it a criminal offence for drivers to allow smoking in their privately owned vehicles when children are present.
The majority of Conservative MPs, 126, voted in favour of the motion, however James Clappison joined with 100 others in his party to oppose it.
The vote was a free one, meaning MPs could make a decision based on their opinions rather than worrying about having to toe the party line.
Mr Clappison said: "I personally am against smoking and I think it is inadvisable for parents to smoke in their cars with their children.
"However I’m not sure making legislation about this is the right thing to do. We have to leave matters like this to the individual and allow them to make up their own minds rather than making it a criminal offence.
"I respect the liberty of my constituents to control their lives, even if I might not approve of their decisions.
"We can’t have the state controlling every aspect of people’s lives. It really is a philosophical issue."
He said the focus should instead be on giving people the facts about the dangers of smoking in cars and allowing them to make up their own minds.