Michael Grosvenor, a modern language teacher at Aylesford school, Kent, had brought the teaching profession into disrepute, England's General Teaching Council said.
Mr Grosvenor, who had taught at the school since 1983, was group leader on a week-long trip to Marchants Hill activity centre, in Surrey. Along with four colleagues, he supervised 50 Year 8 and 9 students and two Year 11 students, acting as prefects, in July 2003.
The panel heard that Mr Grosvenor had organised school trips before, and had drawn up guidelines for procedures six months earlier.
These stressed the importance of supervising pupils in the evenings, and said teachers should not drink excessively and must be able to drive at all times.
Michelle Anderson, the assistant headteacher, said the school had a long-standing tradition of allowing Year 11 pupils to accompany staff on trips and they had permission from parents to have an alcoholic drink.
The panel heard that on the Wednesday and Thursday evenings of the trip, Mr Grosvenor drank whisky and beer with Samantha Burmis and Bruce Crombie, both teachers at the school, in the company of the two female Year 11 students, at the activity centre's bar.
During the Thursday evening he also shared cannabis with one of the students.
On their return to school, the students told the assistant head that teachers played drinking games in the bar and in Mr Grosvenor's room, and that Mr Grosvenor and Miss Burmis had had a sexually explicit conversation on his bed.
The students said the Year 8 and Year 9 pupils had remarked on the teachers' drinking.
One pupil said that on the Friday morning Mr Grosvenor was still drunk and was found asleep on a decking area.
Mr Grosvenor admitted to Ian Carruthers, the head, that he had made "made some stupid, laddish comments" but said Thursday night was just "three people returning from a pleasant evening out".
He admitted that he would have been unable to drive on both mornings after drinking.
The panel heard that Mr Grosvenor had no rota system in place for night-time supervision and that any system that emerged had done so "by default".
He resigned on July 15, 2003.
Aylesford launched an internal investigation into the conduct of the three teachers, who were all found guilty of unacceptable professional conduct.
An allegation of sexual harassment brought by Miss Burmis against Mr Grosvenor was not pursued.
The committee said it had taken into account Mr Grosvenor's remorse and the fact he had an unblemished record.
However, he had brought the profession into disrepute and failed to take care of the pupils and teachers under his supervision.
He had also breached the school's policies on drugs and residential trips.
Mr Grosvenor can apply to go back on the teaching register in two years.