The double Olympic champion was chased hard down the final straight by Turkish pair Ali Kaya and Polat Kemboi Arikan and compatriot Andy Vernon, but never looked in any real danger.
Vernon, hampered by backmarkers at the start of the final lap, pipped the two Kenyan-born Turks to take silver, Kaya was third and Arikan, the defending champion, finished out of the medals.
It was a welcome win for the 31-year-old Farah in what has been a frustrating season.
"It meant a lot to me," Farah told reporters after adding to his 5,000 and 10,000 metres European golds in Barcelona in 2010 and his 5,000 metres title in Helsinki two years ago.
"I was really ill a few weeks ago but training has gone well.
"Winning the European Championships again really does mean a lot to me. I didn't want to let people down after missing the Commonwealth Games, it hasn't been easy."
On a wet and chilly evening at the Letzigrund, Farah went to the front of the pack just over three laps from the end and never looked like relinquishing his lead.
Farah, who won the 5,000 and 10,000 metres titles at the London Olympics and the world championships in Moscow last year, was admitted to hospital in the United States at the start of July with abdominal pains.
He initially said he would compete at both distances in the Commonwealth Games in Glasgow but had to pull out.
He also made an inauspicious competitive debut over 26.2 miles when he finished eighth in the London marathon in April.
Britain also won gold in the men's 100 metres and women's 100 metres hurdles.
James Dasaolu held off Frenchman Christophe Lemaitre to win the 100 in 10.06 seconds and Tiffany Porter won the sprint hurdles in 12.76 seconds, three hundredths of a second ahead of Cindy Billaud of France.
Dafne Schippers of the Netherlands, world championship bronze medallist in the heptathlon last year, made a successful switch to the sprints as she won the women's 100 metres in 11.12 seconds ahead of Myriam Soumare of France and Ashleigh Nelson of Britain.
Schippers will also run in the 200 metres and women's 4x100 metres relay.
- Athletics, Track & Field
- Sports & Recreation
- Andy Vernon