A system and method for linking to accounts using credential-less authentication that includes: within a first application context at an account-linking computing service: receiving a request to establish an account link, establishing the account link to a user account of an account service using user credentials, and receiving user identifying information of the first application context and storing the user identifying information in association with the account link; and within a second application context at the account-linking computing service: receiving user identifying information of the second application context, searching and identifying a candidate account link using the user identifying information of the second application context, verifying eligibility for access to the account link, and permitting access to the account link upon successful verification of eligibility.