City Councilor Michael Ross, a Back Bay Democrat, became the fourth member of the council on Thursday to enter the race for mayor of Boston, posting a message on his new website with plans for a formal campaign launch in May.

Representing the Back Bay, Beacon Hill, West End, Fenway, Kenmore Square, Audubon Circle, and Mission Hill as the District 8 councilor, Ross joins his colleagues Councilors Robert Consalvo, Felix Arroyo and John Connolly seeking the seat that Mayor Thomas Menino will relinquish at the end of the year.

“I love this city," Ross wrote on his new campaign website, recalling his early days on the City Council 13 years ago fighting to save Fenway Park. "I believe in its people and our limitless potential. It’s why, when I formally kick off my campaign in May, you are all invited to hear me share a progressive vision for Boston that is built on the values and diversity of our neighborhoods, and rooted in my upbringing and work on the city council.”

Ross said that he came to appreciate the immigrant experience and the importance of helping newcomers succeed from his father, who was a Holocaust survivor. He also discussed his mother’s influence on his social views.

“My mother, a 71-year-old proud and openly gay woman, taught me that we don't judge people by how they look or who they love, but rather what they do and how they treat others,” Ross said.

Dorchester Rep. Marty Walsh, Suffolk County District Attorney Dan Connolly, community organizer Bill Walczak, activist Will Dorcena and Touch-FM co-founder Charles Clemons are also running for mayor.