A Columbia University custodian who could not speak English when he fled worn-torn Yugoslavia in 1992 will graduate from the Ivy League school with honors this weekend after working toward his degree in classics for 12 years.

"I'm proud and I'm extremely happy," Gac Filipaj told ABC News.

When Filipaj arrived in the US in the early 1990s, he quickly set about learning how to speak English before securing a custodial job at Columbia when a friend told him it was the top school in the city.

He eventually began taking classes on a part-time basis alongside traditional Columbia students under a tuition exemption for the university's employees.

"He's the best study partner I had at Columbia and an amazing person," said fellow student Kathryn Minogue, who took an Ancient Greek language class on the Iliad with Filipaj.

"He was always on time, prepared, focused," she told NewsCore in an email. "I'm the salutatorian of my class (also Gac's class) but he worked far harder than I did to earn this degree."

Filipaj, who still sends most of his salary back to his family in Montenegro, told ABC his only regret was that his father, who died three weeks ago, never knew about his studies at the elite university.

The 52-year-old said he plans to follow up his bachelor's degree with graduate study.

"I would say that I have fulfilled half of my dream -- going to graduate school would complete it," Filipaj said.