In February 2009, he was banned from entering Macau to give a public lecture, which raised strong responses from both pan-democracy and pro-Beijing parties.

[3] Chan was called to the Hong Kong Bar in September 1982, specialising in public law and human rights.

He has appeared as counsel in many leading constitutional law cases, covering a wide spectrum of issues such as free speech, fair trial, election and social welfare rights.

[7] On 27 February 2009, Chan was invited to give a public lecture on the right to a fair trial at the University of Macau.

[8] Legislator Nelson Wong said "it seems that Hong Kong lawmakers, journalists and academics are inferior to gamblers, sex tourists and loan sharks.

[9] Pro-Beijing camp Regina Ip said the SAR government must react since it affects the human rights of citizens.

[9][11] Thought to be front-runner for the post of pro-vice-chancellor for staffing and resources of the University of Hong Kong, and having been unanimously recommended by a search committee of the University in November 2014, Chan was criticised in Wen Wei Po and Ta Kung Pao, two pro-China newspapers, for his liberal pro-democracy stance.

The pro-China newspapers accused Chan of allowing the Faculty to be too involved in politics and for not taking steps to prevent his staff Associate Professor Benny Tai from carrying out the turbulent civic movement of Occupy Central.

According to an article written by Kevin Lau in Ming Pao, parties close to the government applied pressure on committee members behind the scenes to block Chan's appointment.

[17][18] CY Leung's lieutenant Fanny Law, who was found to have interfered with institutional autonomy in 2007 whilst she was Education Secretary,[19] categorically denied having intervened.

[15] The council was criticised when it repeatedly deferred the decision to appoint Chan, stating that it should wait until a new provost was in place.

On 29 September 2015, the council rejected Chan's appointment (by 12 votes to 8) through a secret ballot in a closed meeting; no reason for the decision was provided.