| Cover | Mar. 10, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Mar. 10, 2022 |
| Entity Registrant Name | PORTILLO'S INC. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-40951 |
| Entity Tax Identification Number | 87-1104304 |
| Entity Address, State or Province | IL |
| Entity Address, Address Line One | 2001 Spring Road |
| Entity Address, Address Line Two | Suite 400 |
| Entity Address, City or Town | Oak Brook |
| Entity Address, Postal Zip Code | 60523 |
| City Area Code | 630 |
| Local Phone Number | 954-3773 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Class A Common Stock, $0.01 par value per share |
| Trading Symbol | PTLO |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Amendment Flag | false |
| Entity Central Index Key | 0001871509 |
