With one of his brothers Tsai joined Taipei's Tenth Credit Cooperative in 1960. Two years later, they founded the Cathay Life Insurance Company, which at the time of his death was the largest life insurance company in Taiwan.
He died of heart disease at the age of 81 in Taipei's Cathay General Hospital, which he founded in 1977. He had been hospitalized for six years. Tsai was married to Chou Pao-chin and had seven children.
The family split Cathay Life Insurance in 1979. Tsai Wan-lin founded the Lin Yuan Group with his share. Over the next 10 years, the Lin Yuan Group expanded to become the largest Taiwanese conglomerate. Cathay Financial Holdings, a division of the Lin Yuan Group, became Taiwan's largest financial holding company. Cathay Insurance was renamed Fubon Insurance in 1992.