The crucifer is the primary altar server, and thus has the responsibility to supervise the other servers along with the MC. By ancient tradition, the crucifer at major solemnities should be a tunicled acolyte.
The crucifer carries the processional cross for the entrance procession, for the Gospel Procession, and for the recessional, but he also performs a number of other essential duties in the course of Solemn Mass. The crucifer strikes the bell with the hammer at the appropriate moments, and if there is no MC, he holds the communion paten for the deacon during the communion of the faithful.
Before mass, the crucifer vests in cassock and surplice and makes sure the processional cross sits on the counter of the vestry.
As directed by the acolyte and MC, he takes the cross with him to the sacristy for the preparatory prayers.
For the entrance procession, the crucifer, flanked by the torch bearers, follows the thurifer, several paces behind him.
He holds the cross high when walking with the cross in procession.
Upon arriving at the foot of the altar, the crucifer and torch bearers bow slightly toward the altar, and then turn right and move toward the vestry. The crucifer turns into the back pew and moves through the pew to put the cross away.
He then stands in his place in the pew.
He follows the Order of Mass and the postures of the other servers.
The crucifer remains in his place in the pew during the Gospel.
At the Offertory, when the acolyte sets the chalice on the altar, the crucifer steps up to the credence table and stands ready to present the bread box.
After the censing, he presents the lavabo to the celebrant, then returns to his place at the altar step.
After the response to the Orate Fratres, the crucifer kneels at the cushion in front of the bell. At the Sanctus he strikes the bell three times—once for each "Holy".
He strikes the bell when the celebrant extends his hands over the gifts, saying “Vouchsafe, O God …”
He bows low, kneeling, and then rises and adores, striking the bell at each genuflection, at the elevation, and then the genuflection. Then he bows low again, kneeling upright for the Mysterium Fidei.
As the celebrant turns to show the people the consecrated species, just before he says “The Gifts of God …” he strikes the bell again.
During the communion of the people, the crucifer stands and watches the sacred ministers in case his assistance in needed.
When the ministers return to the altar for the ablutions, the crucifer moves to the credence table to pour the cruets for the ablutions. As prompted by the celebrant, he pours a little wine into the chalice, and then a little wine and a little water over the fingers of the celebrant and the deacon.
When the ablutions are done, he goes back to his place in the pews and kneels.
As soon as the deacon sings the Dismissal, he goes and gets the cross, and stands with the cross in the midst of the chancel, facing the altar. The torch bearers retrieve their candles.
When the celebrant and ministers genuflect and turn for the Recessional, the crucifer turns also, lifts high the cross, and with the torch bearers he recesses, followed by the thurifer.
In the narthex, the crucifer kneels with the other servers and receives the blessing from the celebrant.
The crucifer then goes out the front doors of the church, around and through the vestry door.
He then puts the cross back on its bracket, genuflects, returns to the vestry, and puts away his cassock and surplice.