Giovanni is referred to in documents as "Johannes de Alemanea pictor quondam Johannis," but is also called "Zuane todesco" in the Venetian dialect or, in his signature on some works, "Zuane de Muran" (that is, from Murano). His name appears for the first time, together with that of his brother-in-law Antonio Vivarini, in the signature on an altarpiece painted in 1441 for the church of Santo Stefano in Venice. The work is today conserved in the Kunsthistorisches Museum in Vienna, but the signatures and date have been lost along with the original frame. The joint workshop, located on the island of Murano, produced a number of signed works destined mainly for the churches of Venice: three for the chapel of San Tarasio in the church of San Zaccaria (1443-1444), a large Coronation of the Virgin still in San Pantalon, a triptych representing the Virgin and Child enthroned with four saints for the Scuola Grande della Carità (1446; now in the Gallerie dell'Accademia), and the polyptych of the Nativity and four saints painted for the church of San Francesco in Padua (1447), now in the National Gallery, Prague. In May 1448 the two partners agreed to fresco the vault of the Ovetari chapel in the church of the Eremitani in Padua; two years later Antonio Vivarini informed the patrons of his brother-in-law's death, asking to be paid for the work done to that point and withdrawing from the project.
Nothing is known about Giovanni's origins and training, but his association with a local painter suggests that by the beginning of the 1440s he was fairly well known and had been active in Venice for some time. Rigoni offers an intriguing hypothesis that he is to be identified with Giovanni da Ulm, called in 1437 to fresco the Palazzo Vescovile in Padua. An alternative hypothesis, advanced earlier by Moschetti and recently by Merkel, that he was the "Johannes pictor quondam Nicolai de Alemania" living in Padua in 1423, is less credible because of the differing patronymic.
Various scholars have attempted to distinguish the work of the German painter in the paintings he signed together with Antonio Vivarini, but only since the 1971 publication of a panel in the Walters Art Museum, signed by Giovanni alone and dated 1444, have art historians had a sure point of reference for this task. Another reference point could be the frescoes (Busts of the Evangelists) in the Ovetari chapel (destroyed in 1944 but documented by photographs), presumed to be executed by Giovanni alone because the style differs from Antonio's and because Antonio refused to continue the frescoes after Giovanni's death. Giovanni's guiding role in the workshop seems to be documented by two pieces of evidence: except in the case of the Prague polyptych, his signature appears first on the works he executed with Antonio, and when in 1447 Michele Giambono was commissioned to copy the San Pantalon altarpiece, signed by both artists, the document affirmed that this was a work by "Ser Johannes theothonicj pictoris." If the most recent criticism is correct in ascribing to Giovanni the stories of Saint Apollonia divided among the museums of Bassano, Bergamo, and Washington, his style--despite its undeniable closeness to his partner's manner--is distinguished by a greater refinement, a more evident Gothic accent and, generally, a fairy-tale atmosphere, which persist, albeit modified and developed toward a detailed and imaginative naturalism, in the frescoes in Padua that were interrupted by his death shortly before 9 June 1450. [This is the artist's biography published in the NGA Systematic Catalogue]
 Rigoni 1970, 51-56.
 Moschetti in Lazzarini 1908, 146-150, and Merkel, "Giovanni d'Alemagna,' in Pittura nel Veneto, 1 (1989): 346-347.
 L. Venturi 1907; Gebhart 1912; Planiscig 1922; Fiocco 1948.
 Testi 1915, 306.
Lazzarini, Vittorio. Documenti relativi alla pittura padovana del secolo XV. Illustrations and notes by Andrea Moschetti. Venice, 1908: 146-149.
Gebhardt, Carl. "Giovanni d'Alemagna." Monatschefte für Kunstwissenschaft 5 (1912): 395-403.
Planiscig, Leo. "Un politico sconoscinto di Antonio Vivarini e di Giovanni d'Alemagnga." Bollettino d'Arte n.s. 1 (1922): 427-432.
Fiocco, Giuseppe. "Le pitture venete del castello di Konopiste." AVen 2 (1948): 18-28.
Zeri, Frederico. "Un 'San Gerolamo' firmato di Giovanni d'Alemagna." In Studi di storia dell'arte in onore di Antonio Morassi. Venice, 1971: 40-49.
Christiansen, Keith. "La pittura a Venezia e in Veneto nel primo Quattrocento." In La pittura in Italia: Il Quattrocento. 2 vols. Milan, 1987: 1:142-145.
Merkel, Ettore. "Giovanni d'Alemagna." In La Pittura nel Veneto. Il Quattrocento. Edited by Mauro Lucco. 2 vols. Milan, 1989-1990: 1(1989):346-347.
Massini, M.E. "Giovanni d'Alemagna." In Dictionario biografico degli italiani 55 (2000): 646-649.
Boskovits, Miklós, and David Alan Brown, et al. Italian Paintings of the Fifteenth Century. The Systematic Catalogue of the National Gallery of Art. Washington, D.C., 2003: 315.