Harold Ramis: Actor, writer and director best known for 'Ghostbusters' and 'Groundhog Day' who was acclaimed as a comic giant

Who you gonna call? The Ghostbusters in 1984: left to right, Ramis, Ernie Hudson, Bill Murray and Dan Aykroyd (Rex)

Harold Ramis was the bespectacled sidekick to Bill Murray in Ghostbusters whose early grounding in live comedy led to hit films like Groundhog Day, National Lampoon's Animal House and Caddyshack. In front of the camera he played the lovable geek. Behind it he was one of cinema's most potent comic forces of the 1970s and '80s.

Though he had harboured ambitions as a leading man, he realised he was better as a straight man, or even better as a director of more uninhibited talents like John Belushi or Murray. "As a person of intellect, I could complement John or Bill, who were people of instinct," he once said. "I could help guide and deploy that instinct."

His best-known role was in Ghostbusters, as scientist Egon Spengler (the one with all the ideas), while he also played Murray's fellow army recruit in Stripes. But the Chicago native and early member of the improvisational comedy troupe Second City was the guiding light of a comic wave that included Murray, Belushi, Chevy Chase and Dan Aykroyd. He co-wrote and directed Caddyshack, Groundhog Day and Analyze This and co-wrote Meatballs, Stripes and Ghostbusters.

With a countercultural bent acquired as part of the baby boomer generation, Ramis – who escaped service in Vietnam, he claimed, by checking every box on the medical-history form, though he also claimed to have failed the medical by taking methamphetamine – pushed against institutions: the college dean of Animal House, the country club members of Caddyshack, the drill sergeant of Stripes. He became a Buddhist in midlife, and his spiritual side was to the fore in the wry existentialism of Groundhog Day, the 1993 film in which Murray's arrogant and self-centred TV weatherman, stranded by the winds and snow in small-town America, re-lives a day over and over until he finally gets it right, becomes a good person and breaks the cycle. The film has been hailed by fellow Buddhists for its depiction of rebirth; Catholics, meanwhile, have their own interpretation: Murray is in Purgatory, and remains there until his soul is cleansed.

The son of Chicago shopkeepers, Ramis attended Washington University in St Louis, where he began writing comedy plays: "In my heart, I felt I was a combination of Groucho and Harpo Marx, of Groucho using his wit as a weapon against the upper classes, and of Harpo's antic charm and the fact that he was oddly sexy – he grabs women, pulls their skirts off, and gets away with it." After graduating he worked briefly in a mental institution; he often said, in all seriousness, that the experience helped prepare him for working with actors. He then worked as a writer on his local newspaper before moving to Playboy magazine.

He helped recalibrate the epicentre of American comedy at Second City, which he joined in 1969. He was soon followed by Belushi, Murray and Aykroyd. Chicago, he later said in the book of interviews And Here's the Kicker, conditioned him to living "slightly on the outside of the mainstream." He expanded: "New York and LA were the real centres of culture in America, and we were kind of a sideshow. There's always more comedy in being alienated than in fitting in."

In 1976 he became head writer for the Canadian comedy show Second City Television but soon moved on to bigger projects, beginning with the 1978 knockabout classic hit comedy National Lampoon's Animal House, which he wrote with the National Lampoon co-founder Doug Kenney. Their motto was: "Broad comedy is not necessarily dumb comedy."

With Murray as the comic lead, the Second City old boys paired up for numerous projects: 1979's Meatballs, 1980's Caddyshack, 1981's Stripes. But the best-known of his collaborations with Murray and Aykroyd was Ghostbusters, which he wrote with Aykroyd, who had a fascination with thes paranormal. Aykroyd came up with the idea after reading an article about quantum physics and parapsychology in the American Society of Psychical Research Journal. His original conception, which featured interplanetary travel, was a budgetary impossibility, and at the urging of producer and director Ivan Reitman, Aykroyd and Ramis drafted a more easily realisable script over the course of a few months.

Although it became one of the most successful comedies of the 1980s, spawning a not-quite-as-successful sequel in 1989 and a long-running TV cartoon series, Ramis and Murray fell out during the making of Ghostbusters, and didn't speak for 10 years. It was reported that during the illness that killed Ramis – he had suffered since 2010 from an autoimmune disease that causes inflammation and damage to blood vessels – Murray visited him.

Ramis's last directorial hit was Analyze This (1999), the therapist-meets-mobster comedy starring Billy Crystal and Robert DeNiro. Like many of his later films (1996's Multiplicity, in which Michael Keaton finds cloning to be the answer to the work-life balance, and 1995's Stuart Saves His Family, based on a series of Saturday Night Live sketches), it hinged on a story of personal redemption.

Some of his later efforts (2000's Bedazzled, a lame remake of the 1967 Peter Cook and Dudley Moore comedy, and 2009's Year One) were flops. The Ice Harvest, a 2005 comedy starring John Cusack, was one of the darkest comedies for Ramis, whose humour, however full of rebellion and absurdity, was nearly always optimistic. More recently he directed episodes of the US version of The Office.

His legacy as a father figure to generations of comedians was captured in Judd Apatow's 2007 hit comedy-drama Knocked Up, in which he was cast as Seth Rogen's father – because, as Apatow said, "we all saw him as the dream dad". A third instalment of Ghostbusters has long been rumoured, but is yet to materialise. "The best comedy touches something that's timeless and universal in people," Ramis said in 2009. "When you hit it right, those things last."

Harold Ramis, actor, screenwriter and director: born Chicago 21 November 1944; married 1967 Anne Plotkin (marriage dissolved; one daughter), 1989 Erica Mann (two sons); died Chicago 24 February 2014.