Seamus was Ginny Weasley's second, and became Lieutenant of Gryffindor when she stayed home. He is the Sluagh in the sequel to Dumbledore's Army and the Year of Darkness, Sluagh. He marries Susan MacMillan, and they have a son together, Thomas Icarus Finnigan. Through marrying Sue Cecily became his step-daughter.
Seamus' tattoo is made up of crosses; each bearing the name of one of the fallen DA.