It depends if he is Sephardic or Ashkenazic.
The Shach (Y.D. 265:24) and Magen Avraham (25:28), two major Ashkenazic halachic authorities, record the minhag that men do not remove their tefillin until after the milah. The reason, the Shach explains, is that the Torah describes both tefillin and brit milah as an “ot,” a sign. However, Rav Moshe Pirutinsky in his Sefer Habrit (265:133) cites a number of Acharonim who object to this practice. They argue that the tefillin are a “competing” ot to milah, and thus wearing tefillin during a brit detracts from the ot of brit milah. Moreover, these authorities note that the Gemara (Zevachim 19a) states that kohanim do not wear tefillin during the avodah. This is a relevant point because Chazal compare a brit milah to a korban (see, for example, the Biur Hagra Y.D. 265:40).
Indeed, the Aruch Hashulchan (Y.D. 265:38) notes that the minhag has emerged for men to remove their tefillin before the brit. In my experience, the generally accepted minhag today is that Ashkenazic men remove their tefillin before the brit, except for the father of the baby and the sandek. However, the Mishnah Berurah (25:55) writes that it is “proper” not to remove the tefillin until after the brit milah. Indeed, I once met Rav Reuven Feinstein (the son of Rav Moshe Feinstein) at a brit and noticed that he did not remove his tefillin until after the brit. He told me that this is proper practice for all to follow. Rav Moshe Snow reports that Rav Dovid Feinstein also does not remove his tefillin until after the brit.
Among Sephardim, however, the preferred custom is that even the father and sandek do not wear tefillin at a brit. As noted by Maran HaChida in his work Mar’it Ha’ayin, tefillin has the status of an “ot” (a sign of our covenant with God), and brit milah is likewise considered an “ot.” By wearing tefillin at a brit milah, one appears as though he belittles the brit’s status as an “ot.” Thus, the Chida writes, just as we do not wear tefillin on Shabbat, because Shabbat is considered an “ot,” one should also not wear tefillin at a brit milah. Accordingly, Chacham Ovadia Yosef, both in Teshuvot Yabia Omer (vol. 3, p. 13) and in Sova Smachot (7:2), rules that tefillin should preferably not be worn at a brit milah. Rav Eli Mansour notes that this was also the position of a leading Syrian Jewish rabbi, Chacham Baruch Ben-Haim, who noted that there is often much mingling that takes place just prior to a brit, and it is thus inappropriate to wear tefillin, which requires focus and concentration.
Nevertheless, Rav Mansour writes that one should not object to those who wear tefillin at a brit, even among Sephardim, because there are documented accounts of great Sephardic sages who followed the practice of wearing tefillin. It is reported, for example, that Chacham Ben Zion Abba Shaul (Israel, 1923-1998) put on tefillin when he served as sandek for his grandson, and the great tzadik Chacham Mansur Ben Shimon also wore tefillin at britot. Therefore, notwithstanding the ruling of Chacham Ovadia, those who have a family tradition to wear tefillin at a brit may do so, and others should not object.
According to all opinions, however, if a brit milah takes place on Rosh Chodesh, when the tefillin is removed before Musaf, one should not put the tefillin on again after the prayer service for the brit. Since the tefillin is removed before Musaf, it should not be worn again afterward for the brit, according to all views. This point is made by the Kaf Hachaim (Orach Chaim 25:96) as well as by Chacham Ovadia Yosef, in Yabia Omer (ibid.). In addition, all agree that the father and sandek should wear a tallit during a brit milah.
Among Ashkenazic Jews, it is customary for the father and sandek to wear a tallit and tefillin during a brit milah. The Aruch HaShulchan and Mishnah Beuruah disagree as to whether the other men present at the brit should keep their tefillin on until the brit is completed. Chacham Ovadia Yosef rules that even a father should not wear tefillin during a brit if he is Sephardic. He should, however, wear a tallit. Rav Eli Mansour rules that a Sephardic Jew whose family tradition is to wear tefillin at the brit of his son should maintain his family practice, notwithstanding Chacham Ovadia’s ruling.
By Rabbi Haim Jachter
Rabbi Haim Jachter is the spiritual leader of Congregation Shaarei Orah, the Sephardic Congregation of Teaneck. He also serves as a rebbe at Torah Academy of Bergen County and a dayan on the Beth Din of Elizabeth.